diff --git a/src/test/java/com/google/devtools/build/lib/actions/DigestUtilsTest.java b/src/test/java/com/google/devtools/build/lib/actions/DigestUtilsTest.java
index dbe2cff..f8f0a5f 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/DigestUtilsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/DigestUtilsTest.java
@@ -18,7 +18,6 @@
 import com.google.common.base.Strings;
 import com.google.common.cache.CacheStats;
 import com.google.devtools.build.lib.actions.cache.DigestUtils;
-import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.testutil.TestThread;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.vfs.DigestHashFunction;
@@ -59,7 +58,7 @@
     final CountDownLatch readyLatch = new CountDownLatch(1);   // Used to block main thread.
 
     FileSystem myfs =
-        new InMemoryFileSystem(BlazeClock.instance(), hf) {
+        new InMemoryFileSystem(hf) {
           @Override
           protected byte[] getDigest(Path path) throws IOException {
             try {
@@ -166,7 +165,7 @@
     final AtomicInteger getDigestCounter = new AtomicInteger(0);
 
     FileSystem tracingFileSystem =
-        new InMemoryFileSystem(BlazeClock.instance()) {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           protected byte[] getFastDigest(Path path) {
             getFastDigestCounter.incrementAndGet();
@@ -219,7 +218,7 @@
     final AtomicInteger getDigestCounter = new AtomicInteger(0);
 
     FileSystem tracingFileSystem =
-        new InMemoryFileSystem(BlazeClock.instance()) {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           protected byte[] getFastDigest(Path path) {
             getFastDigestCounter.incrementAndGet();
@@ -261,7 +260,7 @@
   public void manuallyComputeDigest() throws Exception {
     byte[] digest = {1, 2, 3};
     FileSystem noDigestFileSystem =
-        new InMemoryFileSystem(BlazeClock.instance()) {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           protected byte[] getFastDigest(Path path) {
             throw new AssertionError("Unexpected call to getFastDigest");
diff --git a/src/test/java/com/google/devtools/build/lib/actions/MapBasedActionGraphTest.java b/src/test/java/com/google/devtools/build/lib/actions/MapBasedActionGraphTest.java
index fac6aa9..6975b86 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/MapBasedActionGraphTest.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/MapBasedActionGraphTest.java
@@ -24,6 +24,7 @@
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.concurrent.AbstractQueueVisitor;
 import com.google.devtools.build.lib.concurrent.ErrorClassifier;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -39,7 +40,7 @@
  */
 @RunWith(JUnit4.class)
 public class MapBasedActionGraphTest {
-  private final FileSystem fileSystem = new InMemoryFileSystem();
+  private final FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
   private final ActionKeyContext actionKeyContext = new ActionKeyContext();
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java b/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java
index 0f9b914..bd566ad 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/util/ActionsTestUtil.java
@@ -81,6 +81,7 @@
 import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.util.ResourceUsage;
 import com.google.devtools.build.lib.util.io.FileOutErr;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -345,7 +346,8 @@
 
   public static final Artifact DUMMY_ARTIFACT =
       new Artifact.SourceArtifact(
-          ArtifactRoot.asSourceRoot(Root.absoluteRoot(new InMemoryFileSystem())),
+          ArtifactRoot.asSourceRoot(
+              Root.absoluteRoot(new InMemoryFileSystem(DigestHashFunction.SHA256))),
           PathFragment.create("/dummy"),
           NULL_ARTIFACT_OWNER);
 
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/AnalysisWithIOExceptionsTest.java b/src/test/java/com/google/devtools/build/lib/analysis/AnalysisWithIOExceptionsTest.java
index 0b9121b..9486a88 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/AnalysisWithIOExceptionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/AnalysisWithIOExceptionsTest.java
@@ -16,8 +16,8 @@
 import static org.junit.Assert.assertThrows;
 
 import com.google.devtools.build.lib.analysis.util.AnalysisTestCase;
-import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -37,7 +37,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance()) {
+    return new InMemoryFileSystem(DigestHashFunction.SHA256) {
       @Override
       public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
         String crash = crashMessage.apply(path);
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/InterruptedExceptionTest.java b/src/test/java/com/google/devtools/build/lib/analysis/InterruptedExceptionTest.java
index 8be475a..3f514a2 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/InterruptedExceptionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/InterruptedExceptionTest.java
@@ -16,7 +16,7 @@
 import static org.junit.Assert.assertThrows;
 
 import com.google.devtools.build.lib.analysis.util.AnalysisTestCase;
-import com.google.devtools.build.lib.clock.BlazeClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -38,7 +38,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance()) {
+    return new InMemoryFileSystem(DigestHashFunction.SHA256) {
       @Override
       protected Collection<Dirent> readdir(Path path, boolean followSymlinks) throws IOException {
         if (path.toString().contains("causes_interrupt")) {
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/LocationFunctionTest.java b/src/test/java/com/google/devtools/build/lib/analysis/LocationFunctionTest.java
index 12a72a1..8bb793a 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/LocationFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/LocationFunctionTest.java
@@ -25,6 +25,7 @@
 import com.google.devtools.build.lib.analysis.LocationExpander.LocationFunction;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -189,7 +190,7 @@
   }
 
   private static Artifact makeArtifact(String path) {
-    FileSystem fs = new InMemoryFileSystem();
+    FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     if (path.startsWith("/exec/out")) {
       return ActionsTestUtil.createArtifact(
           ArtifactRoot.asDerivedRoot(fs.getPath("/exec"), "out"), fs.getPath(path));
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/DecompressorValueTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/DecompressorValueTest.java
index a1a934d..b355884 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/DecompressorValueTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/DecompressorValueTest.java
@@ -18,6 +18,7 @@
 import static org.junit.Assert.assertThrows;
 
 import com.google.devtools.build.lib.rules.repository.RepositoryFunction.RepositoryFunctionException;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -31,7 +32,7 @@
 @RunWith(JUnit4.class)
 public class DecompressorValueTest {
 
-  private FileSystem fs = new InMemoryFileSystem();
+  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   @Test
   public void testKnownFileExtensionsDoNotThrow() throws Exception {
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/PatchUtilTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/PatchUtilTest.java
index 973712f..773dd79 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/PatchUtilTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/PatchUtilTest.java
@@ -20,6 +20,7 @@
 import com.github.difflib.patch.PatchFailedException;
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.testutil.Scratch;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -39,7 +40,7 @@
 
   @Before
   public final void initializeFileSystemAndDirectories() throws Exception {
-    fs = new InMemoryFileSystem();
+    fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     scratch = new Scratch(fs, "/root");
     root = scratch.dir("/root");
   }
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/StripPrefixedPathTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/StripPrefixedPathTest.java
index 77ecd72..df1ea4d 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/StripPrefixedPathTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/StripPrefixedPathTest.java
@@ -19,6 +19,7 @@
 import com.google.common.base.Optional;
 import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.util.OS;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import org.junit.Test;
@@ -85,7 +86,8 @@
 
   @Test
   public void testDeprefixSymlink() {
-    InMemoryFileSystem fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+    InMemoryFileSystem fileSystem =
+        new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
 
     PathFragment relativeNoPrefix =
         StripPrefixedPath.maybeDeprefixSymlink(
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/TestArchiveDescriptor.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/TestArchiveDescriptor.java
index 01278f8..09c0be6 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/TestArchiveDescriptor.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/TestArchiveDescriptor.java
@@ -68,8 +68,8 @@
   DecompressorDescriptor.Builder createDescriptorBuilder() throws IOException {
     FileSystem testFS =
         OS.getCurrent() == OS.WINDOWS
-            ? new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked())
-            : new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+            ? new JavaIoFileSystem(DigestHashFunction.SHA256)
+            : new UnixFileSystem(DigestHashFunction.SHA256);
 
     // do not rely on TestConstants.JAVATESTS_ROOT end with slash, but ensure separators
     // are not duplicated
diff --git a/src/test/java/com/google/devtools/build/lib/buildeventstream/LastBuildEventTest.java b/src/test/java/com/google/devtools/build/lib/buildeventstream/LastBuildEventTest.java
index 2062c57..2a2d6cc 100644
--- a/src/test/java/com/google/devtools/build/lib/buildeventstream/LastBuildEventTest.java
+++ b/src/test/java/com/google/devtools/build/lib/buildeventstream/LastBuildEventTest.java
@@ -33,7 +33,7 @@
 
   @Test
   public void testForwardsReferencedLocalFilesCall() {
-    FileSystem fs = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fs = new UnixFileSystem(DigestHashFunction.SHA256);
     LocalFile localFile = new LocalFile(fs.getPath("/some/file"), LocalFileType.FAILED_TEST_OUTPUT);
     LastBuildEvent event = new LastBuildEvent(new BuildEvent() {
       @Override
diff --git a/src/test/java/com/google/devtools/build/lib/buildeventstream/LocalFilesArtifactUploaderTest.java b/src/test/java/com/google/devtools/build/lib/buildeventstream/LocalFilesArtifactUploaderTest.java
index 5d51abe..fd54172 100644
--- a/src/test/java/com/google/devtools/build/lib/buildeventstream/LocalFilesArtifactUploaderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/buildeventstream/LocalFilesArtifactUploaderTest.java
@@ -19,6 +19,7 @@
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.devtools.build.lib.buildeventstream.BuildEvent.LocalFile;
 import com.google.devtools.build.lib.buildeventstream.BuildEvent.LocalFile.LocalFileType;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -31,7 +32,7 @@
 /** Tests for {@link LocalFilesArtifactUploader} */
 @RunWith(JUnit4.class)
 public class LocalFilesArtifactUploaderTest {
-  private final FileSystem fileSystem = new InMemoryFileSystem();
+  private final FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
   private final LocalFilesArtifactUploader artifactUploader = new LocalFilesArtifactUploader();
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/BUILD b/src/test/java/com/google/devtools/build/lib/buildtool/BUILD
index 4001b7f..e00b933 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/BUILD
@@ -572,6 +572,7 @@
     name = "IoHookTestCase",
     srcs = ["IoHookTestCase.java"],
     deps = [
+        "//java/com/google/devtools/build/lib/google/vfs:google-hash-functions",
         "//src/main/java/com/google/devtools/build/lib/skyframe:mutable_supplier",
         "//src/main/java/com/google/devtools/build/lib/unix",
         "//src/main/java/com/google/devtools/build/lib/vfs",
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/CustomRealFilesystemBuildIntegrationTest.java b/src/test/java/com/google/devtools/build/lib/buildtool/CustomRealFilesystemBuildIntegrationTest.java
index fdbe97d..11be955 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/CustomRealFilesystemBuildIntegrationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/CustomRealFilesystemBuildIntegrationTest.java
@@ -262,7 +262,7 @@
     private final Set<String> createDirectoryErrorNames = new HashSet<>();
 
     private CustomRealFilesystem() {
-      super(DigestHashFunction.getDefaultUnchecked());
+      super(DigestHashFunction.SHA256);
     }
 
     void alwaysError(Path path) {
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/InconsistentFilesystemTest.java b/src/test/java/com/google/devtools/build/lib/buildtool/InconsistentFilesystemTest.java
index ed66745..0e073d2 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/InconsistentFilesystemTest.java
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/InconsistentFilesystemTest.java
@@ -38,7 +38,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new UnixFileSystem(DigestHashFunction.getDefaultUnchecked()) {
+    return new UnixFileSystem(DigestHashFunction.SHA256) {
       boolean threwException = false;
 
       @Override
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/IoHookTestCase.java b/src/test/java/com/google/devtools/build/lib/buildtool/IoHookTestCase.java
index 31d65ab..2d7651f 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/IoHookTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/IoHookTestCase.java
@@ -14,11 +14,11 @@
 package com.google.devtools.build.lib.buildtool;
 
 import com.google.devtools.build.lib.buildtool.util.GoogleBuildIntegrationTestCase;
+import com.google.devtools.build.lib.google.vfs.GoogleHashFunctions;
 import com.google.devtools.build.lib.skyframe.MutableSupplier;
 import com.google.devtools.build.lib.testutil.Suite;
 import com.google.devtools.build.lib.testutil.TestSpec;
 import com.google.devtools.build.lib.unix.UnixFileSystem;
-import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -63,7 +63,7 @@
   @Override
   protected FileSystem createFileSystem() {
     setListener(DUMMY_LISTENER);
-    return new UnixFileSystem(DigestHashFunction.getDefaultUnchecked()) {
+    return new UnixFileSystem(GoogleHashFunctions.PSHA2) {
       @Override
       protected void chmod(Path path, int chmod) throws IOException {
         listener.get().handle(PathOp.CHMOD, path);
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/ProgressReportingTest.java b/src/test/java/com/google/devtools/build/lib/buildtool/ProgressReportingTest.java
index 7262caf..f3345cd 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/ProgressReportingTest.java
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/ProgressReportingTest.java
@@ -64,7 +64,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new UnixFileSystem(DigestHashFunction.getDefaultUnchecked()) {
+    return new UnixFileSystem(DigestHashFunction.SHA256) {
 
       private void recordAccess(PathOp op, Path path) {
         if (receiver != null) {
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/SymlinkForestTest.java b/src/test/java/com/google/devtools/build/lib/buildtool/SymlinkForestTest.java
index 40cb14a..828a5e3 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/SymlinkForestTest.java
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/SymlinkForestTest.java
@@ -29,6 +29,7 @@
 import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.testutil.TestConstants;
 import com.google.devtools.build.lib.util.AbruptExitException;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -59,7 +60,7 @@
   @Before
   public final void initializeFileSystem() throws Exception {
     ManualClock clock = new ManualClock();
-    fileSystem = new InMemoryFileSystem(clock);
+    fileSystem = new InMemoryFileSystem(clock, DigestHashFunction.SHA256);
     linkRoot = fileSystem.getPath("/linkRoot");
     linkRoot.createDirectoryAndParents();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/exec/BlazeExecutorTest.java b/src/test/java/com/google/devtools/build/lib/exec/BlazeExecutorTest.java
index cfe4412..7a7b88e 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/BlazeExecutorTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/BlazeExecutorTest.java
@@ -31,6 +31,7 @@
 import com.google.devtools.build.lib.exec.util.TestExecutorBuilder;
 import com.google.devtools.build.lib.testutil.Suite;
 import com.google.devtools.build.lib.testutil.TestSpec;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import com.google.devtools.common.options.OptionsParser;
@@ -49,7 +50,7 @@
 
   @Before
   public final void setUpDirectoriesAndTools() throws Exception {
-    fileSystem = new InMemoryFileSystem();
+    fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     directories =
         new BlazeDirectories(
             new ServerDirectories(
diff --git a/src/test/java/com/google/devtools/build/lib/exec/SingleBuildFileCacheTest.java b/src/test/java/com/google/devtools/build/lib/exec/SingleBuildFileCacheTest.java
index a251667..fee93f5 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/SingleBuildFileCacheTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/SingleBuildFileCacheTest.java
@@ -22,6 +22,7 @@
 import com.google.devtools.build.lib.actions.DigestOfDirectoryException;
 import com.google.devtools.build.lib.testutil.Suite;
 import com.google.devtools.build.lib.testutil.TestSpec;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -51,7 +52,7 @@
     calls = new HashMap<>();
     digestOverrides = new HashMap<>();
     fs =
-        new InMemoryFileSystem() {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           protected InputStream getInputStream(Path path) throws IOException {
             int c = calls.containsKey(path.toString()) ? calls.get(path.toString()) : 0;
diff --git a/src/test/java/com/google/devtools/build/lib/exec/SpawnInputExpanderTest.java b/src/test/java/com/google/devtools/build/lib/exec/SpawnInputExpanderTest.java
index a94e211..f8a2d67 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/SpawnInputExpanderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/SpawnInputExpanderTest.java
@@ -40,6 +40,7 @@
 import com.google.devtools.build.lib.analysis.RunfilesSupplierImpl;
 import com.google.devtools.build.lib.exec.util.FakeActionInputFileCache;
 import com.google.devtools.build.lib.exec.util.SpawnBuilder;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -63,7 +64,7 @@
   private static final ArtifactExpander NO_ARTIFACT_EXPANDER =
       (a, b) -> fail("expected no interactions");
 
-  private final FileSystem fs = new InMemoryFileSystem();
+  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
   private final Path execRoot = fs.getPath("/root");
   private final ArtifactRoot rootDir = ArtifactRoot.asDerivedRoot(execRoot, "out");
 
diff --git a/src/test/java/com/google/devtools/build/lib/exec/StreamedTestOutputTest.java b/src/test/java/com/google/devtools/build/lib/exec/StreamedTestOutputTest.java
index 66ee73a..78eccec 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/StreamedTestOutputTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/StreamedTestOutputTest.java
@@ -19,6 +19,7 @@
 import com.google.common.base.Strings;
 import com.google.common.io.ByteStreams;
 import com.google.devtools.build.lib.util.io.OutErr;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -33,7 +34,7 @@
 @RunWith(JUnit4.class)
 public class StreamedTestOutputTest {
 
-  private final InMemoryFileSystem fileSystem = new InMemoryFileSystem();
+  private final InMemoryFileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   @Test
   public void testEmptyFile() throws IOException {
diff --git a/src/test/java/com/google/devtools/build/lib/exec/SymlinkTreeHelperTest.java b/src/test/java/com/google/devtools/build/lib/exec/SymlinkTreeHelperTest.java
index e510e4e..8bb5fa8 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/SymlinkTreeHelperTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/SymlinkTreeHelperTest.java
@@ -21,6 +21,7 @@
 import com.google.devtools.build.lib.actions.FilesetOutputSymlink;
 import com.google.devtools.build.lib.actions.HasDigest;
 import com.google.devtools.build.lib.shell.Command;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -33,7 +34,7 @@
 /** Unit tests for {@link SymlinkTreeHelper}. */
 @RunWith(JUnit4.class)
 public final class SymlinkTreeHelperTest {
-  private final FileSystem fs = new InMemoryFileSystem();
+  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   @Test
   public void checkCreatedSpawn() {
diff --git a/src/test/java/com/google/devtools/build/lib/exec/local/LocalSpawnRunnerTest.java b/src/test/java/com/google/devtools/build/lib/exec/local/LocalSpawnRunnerTest.java
index caa33ab..25db4eb 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/local/LocalSpawnRunnerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/local/LocalSpawnRunnerTest.java
@@ -313,7 +313,7 @@
     SubprocessBuilder.setDefaultSubprocessFactory(new SubprocessInterceptor());
     resourceManager.setAvailableResources(
         ResourceSet.create(/*memoryMb=*/1, /*cpuUsage=*/1, /*localTestCount=*/1));
-    return new InMemoryFileSystem();
+    return new InMemoryFileSystem(DigestHashFunction.SHA256);
   }
 
   private static ProcessWrapper makeProcessWrapper(FileSystem fs, LocalExecutionOptions options) {
@@ -642,7 +642,7 @@
 
     File tempDirFile = TestUtils.makeTempDir();
     tempDirFile.deleteOnExit();
-    FileSystem fs = new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fs = new JavaIoFileSystem(DigestHashFunction.SHA256);
     Path tempDir = fs.getPath(tempDirFile.getPath());
 
     LocalSpawnRunner runner =
@@ -884,7 +884,7 @@
     // TODO(b/62588075) Currently no process-wrapper or execution statistics support in Windows.
     assumeTrue(OS.getCurrent() != OS.WINDOWS);
 
-    FileSystem fs = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fs = new UnixFileSystem(DigestHashFunction.SHA256);
 
     LocalExecutionOptions options = Options.getDefaults(LocalExecutionOptions.class);
     options.collectLocalExecutionStatistics = true;
@@ -956,7 +956,7 @@
     // TODO(b/62588075) Currently no process-wrapper or execution statistics support in Windows.
     assumeTrue(OS.getCurrent() != OS.WINDOWS);
 
-    FileSystem fs = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fs = new UnixFileSystem(DigestHashFunction.SHA256);
 
     LocalExecutionOptions options = Options.getDefaults(LocalExecutionOptions.class);
     options.collectLocalExecutionStatistics = false;
diff --git a/src/test/java/com/google/devtools/build/lib/packages/util/PackageFactoryTestBase.java b/src/test/java/com/google/devtools/build/lib/packages/util/PackageFactoryTestBase.java
index c829ae7..45b61ae 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/util/PackageFactoryTestBase.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/util/PackageFactoryTestBase.java
@@ -34,6 +34,7 @@
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.util.Pair;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -108,7 +109,7 @@
   @Before
   public final void initializeFileSystem() throws Exception {
     FileSystem fs =
-        new InMemoryFileSystem() {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           public Collection<Dirent> readdir(Path path, boolean followSymlinks) throws IOException {
             if (path.equals(throwOnReaddir)) {
diff --git a/src/test/java/com/google/devtools/build/lib/pkgcache/BuildFileModificationTest.java b/src/test/java/com/google/devtools/build/lib/pkgcache/BuildFileModificationTest.java
index 05c3c01..5e1b1df 100644
--- a/src/test/java/com/google/devtools/build/lib/pkgcache/BuildFileModificationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/pkgcache/BuildFileModificationTest.java
@@ -37,6 +37,7 @@
 import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.testutil.SkyframeExecutorTestHelper;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
@@ -133,7 +134,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(clock);
+    return new InMemoryFileSystem(clock, DigestHashFunction.SHA256);
   }
 
   private void invalidatePackages() throws InterruptedException {
diff --git a/src/test/java/com/google/devtools/build/lib/pkgcache/IOExceptionsTest.java b/src/test/java/com/google/devtools/build/lib/pkgcache/IOExceptionsTest.java
index 8c087cc..fb240b6 100644
--- a/src/test/java/com/google/devtools/build/lib/pkgcache/IOExceptionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/pkgcache/IOExceptionsTest.java
@@ -18,12 +18,12 @@
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
-import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.packages.ConstantRuleVisibility;
 import com.google.devtools.build.lib.packages.util.PackageLoadingTestCase;
 import com.google.devtools.build.lib.skyframe.TransitiveTargetKey;
 import com.google.devtools.build.lib.skyframe.TransitiveTargetValue;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
@@ -82,7 +82,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance()) {
+    return new InMemoryFileSystem(DigestHashFunction.SHA256) {
       @Nullable
       @Override
       public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
diff --git a/src/test/java/com/google/devtools/build/lib/pkgcache/IncrementalLoadingTest.java b/src/test/java/com/google/devtools/build/lib/pkgcache/IncrementalLoadingTest.java
index 6c30098..f3fb527 100644
--- a/src/test/java/com/google/devtools/build/lib/pkgcache/IncrementalLoadingTest.java
+++ b/src/test/java/com/google/devtools/build/lib/pkgcache/IncrementalLoadingTest.java
@@ -49,6 +49,7 @@
 import com.google.devtools.build.lib.testutil.SkyframeExecutorTestHelper;
 import com.google.devtools.build.lib.util.AbruptExitException;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
@@ -88,7 +89,7 @@
   public final void createTester() throws Exception {
     ManualClock clock = new ManualClock();
     FileSystem fs =
-        new InMemoryFileSystem(clock) {
+        new InMemoryFileSystem(clock, DigestHashFunction.SHA256) {
           @Override
           public Collection<Dirent> readdir(Path path, boolean followSymlinks) throws IOException {
             if (path.equals(throwOnReaddir)) {
diff --git a/src/test/java/com/google/devtools/build/lib/pkgcache/LoadingPhaseRunnerTest.java b/src/test/java/com/google/devtools/build/lib/pkgcache/LoadingPhaseRunnerTest.java
index 1d5eb6f..60ceca3 100644
--- a/src/test/java/com/google/devtools/build/lib/pkgcache/LoadingPhaseRunnerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/pkgcache/LoadingPhaseRunnerTest.java
@@ -61,6 +61,7 @@
 import com.google.devtools.build.lib.util.DetailedExitCode;
 import com.google.devtools.build.lib.util.ExitCode;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
 import com.google.devtools.build.lib.vfs.Path;
@@ -1470,7 +1471,7 @@
     private final Map<Path, IOException> pathsToErrorOnGetInputStream = Maps.newHashMap();
 
     CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock);
+      super(manualClock, DigestHashFunction.SHA256);
     }
 
     synchronized void throwExceptionOnGetInputStream(Path path, IOException exn) {
diff --git a/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorIOTest.java b/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorIOTest.java
index 3a3e4d2..c9dc41f 100644
--- a/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorIOTest.java
+++ b/src/test/java/com/google/devtools/build/lib/pkgcache/TargetPatternEvaluatorIOTest.java
@@ -17,6 +17,7 @@
 import com.google.common.truth.Truth;
 import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.events.EventKind;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
@@ -35,8 +36,6 @@
 /** TargetPatternEvaluator tests that require a custom filesystem. */
 @RunWith(JUnit4.class)
 public class TargetPatternEvaluatorIOTest extends AbstractTargetPatternEvaluatorTest {
-  private static final String FS_ROOT = "/fsg";
-
   private static class Transformer {
     @SuppressWarnings("unused")
     @Nullable
@@ -56,7 +55,7 @@
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance()) {
+    return new InMemoryFileSystem(DigestHashFunction.SHA256) {
       @Override
       public FileStatus stat(Path path, boolean followSymlinks) throws IOException {
         FileStatus defaultResult = super.stat(path, followSymlinks);
diff --git a/src/test/java/com/google/devtools/build/lib/profiler/AutoProfilerBenchmark.java b/src/test/java/com/google/devtools/build/lib/profiler/AutoProfilerBenchmark.java
index e5f3c21..c8d52ed 100644
--- a/src/test/java/com/google/devtools/build/lib/profiler/AutoProfilerBenchmark.java
+++ b/src/test/java/com/google/devtools/build/lib/profiler/AutoProfilerBenchmark.java
@@ -17,6 +17,7 @@
 import com.google.caliper.Benchmark;
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.clock.BlazeClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import java.util.UUID;
 
@@ -31,7 +32,7 @@
     Profiler.instance()
         .start(
             ImmutableSet.copyOf(ProfilerTask.values()),
-            new InMemoryFileSystem().getPath("/out.dat").getOutputStream(),
+            new InMemoryFileSystem(DigestHashFunction.SHA256).getPath("/out.dat").getOutputStream(),
             Profiler.Format.JSON_TRACE_FILE_FORMAT,
             "dummy_output_base",
             UUID.randomUUID(),
diff --git a/src/test/java/com/google/devtools/build/lib/query2/testutil/SkyframeQueryHelper.java b/src/test/java/com/google/devtools/build/lib/query2/testutil/SkyframeQueryHelper.java
index a714600..c2ec706 100644
--- a/src/test/java/com/google/devtools/build/lib/query2/testutil/SkyframeQueryHelper.java
+++ b/src/test/java/com/google/devtools/build/lib/query2/testutil/SkyframeQueryHelper.java
@@ -59,6 +59,7 @@
 import com.google.devtools.build.lib.testutil.TestPackageFactoryBuilderFactory;
 import com.google.devtools.build.lib.util.AbruptExitException;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -81,7 +82,8 @@
 /** An implementation of AbstractQueryHelper to support testing bazel query. */
 public abstract class SkyframeQueryHelper extends AbstractQueryHelper<Target> {
   protected SkyframeExecutor skyframeExecutor;
-  protected FileSystem fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+  protected FileSystem fileSystem =
+      new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
   protected Path rootDirectory;
   protected BlazeDirectories directories;
   private String toolsRepository;
diff --git a/src/test/java/com/google/devtools/build/lib/remote/RemoteModuleTest.java b/src/test/java/com/google/devtools/build/lib/remote/RemoteModuleTest.java
index 47165f0..a573980 100644
--- a/src/test/java/com/google/devtools/build/lib/remote/RemoteModuleTest.java
+++ b/src/test/java/com/google/devtools/build/lib/remote/RemoteModuleTest.java
@@ -44,6 +44,8 @@
 import com.google.devtools.build.lib.runtime.commands.BuildCommand;
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.util.AbruptExitException;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
+import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import com.google.devtools.common.options.Options;
 import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsParsingResult;
@@ -82,7 +84,7 @@
     when(options.getOptions(AuthAndTLSOptions.class)).thenReturn(authAndTLSOptions);
 
     String productName = "bazel";
-    Scratch scratch = new Scratch();
+    Scratch scratch = new Scratch(new InMemoryFileSystem(DigestHashFunction.SHA256));
     ServerDirectories serverDirectories =
         new ServerDirectories(
             scratch.dir("install"), scratch.dir("output"), scratch.dir("user_root"));
diff --git a/src/test/java/com/google/devtools/build/lib/rules/android/ResourceTestBase.java b/src/test/java/com/google/devtools/build/lib/rules/android/ResourceTestBase.java
index 84a191b..6577abd 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/android/ResourceTestBase.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/android/ResourceTestBase.java
@@ -35,6 +35,7 @@
 import com.google.devtools.build.lib.events.ExtendedEventHandler;
 import com.google.devtools.build.lib.events.StoredEventHandler;
 import com.google.devtools.build.lib.skyframe.ConfiguredTargetKey;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Root;
@@ -184,7 +185,7 @@
   @Before
   public void setup() throws Exception {
     errorConsumer = new FakeRuleErrorConsumer();
-    fileSystem = new InMemoryFileSystem();
+    fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     root = ArtifactRoot.asSourceRoot(Root.fromPath(fileSystem.getPath("/")));
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/HeaderDiscoveryTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/HeaderDiscoveryTest.java
index 6f35ce0..d310b27 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/HeaderDiscoveryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/HeaderDiscoveryTest.java
@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -39,7 +40,7 @@
 public class HeaderDiscoveryTest {
   private static final String DERIVED_SEGMENT = "derived";
 
-  private final FileSystem fs = new InMemoryFileSystem();
+  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
   private final Path execRoot = fs.getPath("/execroot");
   private final Path derivedRoot = execRoot.getChild(DERIVED_SEGMENT);
   private final ArtifactRoot artifactRoot = ArtifactRoot.asDerivedRoot(execRoot, DERIVED_SEGMENT);
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/ShowIncludesFilterTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/ShowIncludesFilterTest.java
index ee5c2ff..1d7239d 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/ShowIncludesFilterTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/ShowIncludesFilterTest.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import java.io.ByteArrayOutputStream;
@@ -41,7 +42,7 @@
     showIncludesFilter = new ShowIncludesFilter("foo.cpp");
     output = new ByteArrayOutputStream();
     filterOutputStream = showIncludesFilter.getFilteredOutputStream(output);
-    fs = new InMemoryFileSystem();
+    fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     fs.getPath("/out").createDirectory();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java b/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java
index 80a58ec..1607015 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java
@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.rules.objc.ObjcProvider.Key;
 import com.google.devtools.build.lib.syntax.StarlarkSemantics;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import java.lang.reflect.Field;
@@ -55,7 +56,9 @@
 
   private static Artifact createArtifact(String path) {
     return ActionsTestUtil.createArtifact(
-        ArtifactRoot.asSourceRoot(Root.absoluteRoot(new InMemoryFileSystem())), path);
+        ArtifactRoot.asSourceRoot(
+            Root.absoluteRoot(new InMemoryFileSystem(DigestHashFunction.SHA256))),
+        path);
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilderTest.java b/src/test/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilderTest.java
index 6c30534..4f5acb1 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilderTest.java
@@ -39,6 +39,7 @@
 import com.google.devtools.build.lib.syntax.Location;
 import com.google.devtools.build.lib.util.LazyString;
 import com.google.devtools.build.lib.util.Pair;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import javax.annotation.Nullable;
@@ -50,7 +51,8 @@
 @RunWith(JUnit4.class)
 public class ProtoCompileActionBuilderTest {
 
-  private static final InMemoryFileSystem FILE_SYSTEM = new InMemoryFileSystem();
+  private static final InMemoryFileSystem FILE_SYSTEM =
+      new InMemoryFileSystem(DigestHashFunction.SHA256);
   private final ArtifactRoot root =
       ArtifactRoot.asSourceRoot(Root.fromPath(FILE_SYSTEM.getPath("/")));
   private final ArtifactRoot derivedRoot =
diff --git a/src/test/java/com/google/devtools/build/lib/runtime/BlazeRuntimeTest.java b/src/test/java/com/google/devtools/build/lib/runtime/BlazeRuntimeTest.java
index df5beb6..2688270 100644
--- a/src/test/java/com/google/devtools/build/lib/runtime/BlazeRuntimeTest.java
+++ b/src/test/java/com/google/devtools/build/lib/runtime/BlazeRuntimeTest.java
@@ -26,6 +26,7 @@
 import com.google.devtools.build.lib.server.FailureDetails.Crash.Code;
 import com.google.devtools.build.lib.server.FailureDetails.FailureDetail;
 import com.google.devtools.build.lib.util.DetailedExitCode;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import com.google.devtools.common.options.OptionsBase;
@@ -100,7 +101,7 @@
 
   @Test
   public void crashTest() throws Exception {
-    FileSystem fs = new InMemoryFileSystem();
+    FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     ServerDirectories serverDirectories =
         new ServerDirectories(
             fs.getPath("/install"), fs.getPath("/output"), fs.getPath("/output_user"));
@@ -153,7 +154,7 @@
 
   @Test
   public void addsCommandsFromModules() throws Exception {
-    FileSystem fs = new InMemoryFileSystem();
+    FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     ServerDirectories serverDirectories =
         new ServerDirectories(
             fs.getPath("/install"), fs.getPath("/output"), fs.getPath("/output_user"));
diff --git a/src/test/java/com/google/devtools/build/lib/runtime/LocationPrinterTest.java b/src/test/java/com/google/devtools/build/lib/runtime/LocationPrinterTest.java
index 9bc747e..017409d 100644
--- a/src/test/java/com/google/devtools/build/lib/runtime/LocationPrinterTest.java
+++ b/src/test/java/com/google/devtools/build/lib/runtime/LocationPrinterTest.java
@@ -17,6 +17,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.syntax.Location;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.Root;
@@ -28,7 +29,7 @@
 /** Tests for {@link LocationPrinter} static methods. */
 @RunWith(JUnit4.class)
 public class LocationPrinterTest {
-  private final FileSystem fileSystem = new InMemoryFileSystem();
+  private final FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   @Test
   public void getRelativeLocationString_PathIsAlreadyRelative() {
diff --git a/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperTest.java b/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperTest.java
index b0b1a5f..d63edc7 100644
--- a/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperTest.java
+++ b/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperTest.java
@@ -19,6 +19,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.ExecutionRequirements;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -38,7 +39,7 @@
 
   @Before
   public void setUp() {
-    testFS = new InMemoryFileSystem();
+    testFS = new InMemoryFileSystem(DigestHashFunction.SHA256);
   }
 
   private Path makeProcessWrapperBin(String path) throws IOException {
diff --git a/src/test/java/com/google/devtools/build/lib/runtime/TestSummaryTest.java b/src/test/java/com/google/devtools/build/lib/runtime/TestSummaryTest.java
index 1f6f6f1..28a38fc 100644
--- a/src/test/java/com/google/devtools/build/lib/runtime/TestSummaryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/runtime/TestSummaryTest.java
@@ -38,6 +38,7 @@
 import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.util.io.AnsiTerminalPrinter;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -73,7 +74,7 @@
 
   @Before
   public final void createFileSystem() throws Exception  {
-    fs = new InMemoryFileSystem(BlazeClock.instance());
+    fs = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     stubTarget = stubTarget();
     basicBuilder = getTemplateBuilder();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/AbstractContainerizingSandboxedSpawnTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/AbstractContainerizingSandboxedSpawnTest.java
index 3634968..d66cfb5 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/AbstractContainerizingSandboxedSpawnTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/AbstractContainerizingSandboxedSpawnTest.java
@@ -20,6 +20,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxOutputs;
 import com.google.devtools.build.lib.testutil.TestUtils;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -40,7 +41,7 @@
 
   @Test
   public void testMoveOutputs() throws Exception {
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path testRoot = fileSystem.getPath(TestUtils.tmpDir());
     testRoot.createDirectoryAndParents();
 
@@ -115,6 +116,10 @@
   @Test
   public void testMoveOutputs_warnOnceIfCopyHappened() throws Exception {
     class MultipleDeviceFS extends InMemoryFileSystem {
+      MultipleDeviceFS() {
+        super(DigestHashFunction.SHA256);
+      }
+
       @Override
       public void renameTo(Path source, Path target) throws IOException {
         throw new IOException("EXDEV");
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/BaseRealSandboxfsProcessTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/BaseRealSandboxfsProcessTest.java
index 21de6e9..1a9d9df 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/BaseRealSandboxfsProcessTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/BaseRealSandboxfsProcessTest.java
@@ -65,7 +65,7 @@
 
   @Before
   public void setUp() throws Exception {
-    fileSystem = new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked());
+    fileSystem = new JavaIoFileSystem(DigestHashFunction.SHA256);
     tmpDir = fileSystem.getPath(System.getenv("TEST_TMPDIR")).getRelative("test");
     tmpDir.createDirectory();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessIntegrationTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessIntegrationTest.java
index 2b0bd63..683a277 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessIntegrationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessIntegrationTest.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
 
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -32,7 +33,7 @@
 
   @Override
   Path newTmpDir() throws IOException {
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path tmpDir = fileSystem.getPath("/tmp");
     tmpDir.createDirectory();
     return tmpDir;
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/LinuxSandboxUtilTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/LinuxSandboxUtilTest.java
index e5eafd0..bac5b53 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/LinuxSandboxUtilTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/LinuxSandboxUtilTest.java
@@ -20,6 +20,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSortedMap;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -37,7 +38,7 @@
 
   @Before
   public final void createFileSystem() {
-    testFS = new InMemoryFileSystem();
+    testFS = new InMemoryFileSystem(DigestHashFunction.SHA256);
   }
 
   @Test
@@ -97,7 +98,7 @@
     boolean useFakeHostname = true;
     boolean useDebugMode = true;
 
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path workDir = fileSystem.getPath("/work");
     Path concreteDir = workDir.getRelative("concrete");
     Path sandboxDir = workDir.getRelative("sandbox");
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/RealSandboxfsProcessIntegrationTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/RealSandboxfsProcessIntegrationTest.java
index adc57d5..c162449 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/RealSandboxfsProcessIntegrationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/RealSandboxfsProcessIntegrationTest.java
@@ -35,7 +35,7 @@
       fail("Test requires TEST_TMPDIR to be defined in the environment");
     }
 
-    FileSystem fileSystem = new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fileSystem = new JavaIoFileSystem(DigestHashFunction.SHA256);
     Path tmpDir = fileSystem.getPath(rawTmpDir);
     if (!tmpDir.isDirectory()) {
       fail("TEST_TMPDIR must point to a directory");
@@ -50,7 +50,7 @@
       fail("Test requires SANDBOXFS to be defined in the environment");
     }
 
-    FileSystem fileSystem = new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fileSystem = new JavaIoFileSystem(DigestHashFunction.SHA256);
     Path sandboxfs = fileSystem.getPath(rawSandboxfs);
     if (!sandboxfs.isExecutable()) {
       fail("SANDBOXFS must point to an executable binary");
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/SandboxfsSandboxedSpawnTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/SandboxfsSandboxedSpawnTest.java
index c3d37b2..f843bd7 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/SandboxfsSandboxedSpawnTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/SandboxfsSandboxedSpawnTest.java
@@ -22,6 +22,7 @@
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxInputs;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxOutputs;
 import com.google.devtools.build.lib.testutil.TestUtils;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -44,7 +45,7 @@
 
   @Before
   public final void setupTestDirs() throws IOException {
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     testRoot = fileSystem.getPath(TestUtils.tmpDir());
     testRoot.createDirectoryAndParents();
 
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/SymlinkedSandboxedSpawnTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/SymlinkedSandboxedSpawnTest.java
index 97321e5..643b0e3 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/SymlinkedSandboxedSpawnTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/SymlinkedSandboxedSpawnTest.java
@@ -21,6 +21,7 @@
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxInputs;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxOutputs;
 import com.google.devtools.build.lib.testutil.TestUtils;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -43,7 +44,7 @@
 
   @Before
   public final void setupTestDirs() throws IOException {
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path testRoot = fileSystem.getPath(TestUtils.tmpDir());
     testRoot.createDirectoryAndParents();
 
diff --git a/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java b/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java
index f49f644..3140e6f 100644
--- a/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java
@@ -36,6 +36,7 @@
 import com.google.devtools.build.lib.testutil.TestSpec;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.util.io.OutErr;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -69,7 +70,7 @@
   private static final int SERVER_PID = 42;
   private static final String REQUEST_COOKIE = "request-cookie";
 
-  private final FileSystem fileSystem = new InMemoryFileSystem();
+  private final FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
   private Path serverDirectory;
   private GrpcServerImpl serverImpl;
   private Server server;
diff --git a/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java b/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java
index 5d43f9e..4896549 100644
--- a/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java
+++ b/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java
@@ -18,6 +18,7 @@
 import static java.nio.charset.StandardCharsets.US_ASCII;
 import static org.junit.Assert.assertThrows;
 
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -40,7 +41,7 @@
 
   @Before
   public void setUp() {
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     pidFile = fileSystem.getPath("/pid");
     underTest =
         new PidFileWatcher(
diff --git a/src/test/java/com/google/devtools/build/lib/server/ShutdownHooksTest.java b/src/test/java/com/google/devtools/build/lib/server/ShutdownHooksTest.java
index 711860b..a9da34d 100644
--- a/src/test/java/com/google/devtools/build/lib/server/ShutdownHooksTest.java
+++ b/src/test/java/com/google/devtools/build/lib/server/ShutdownHooksTest.java
@@ -16,6 +16,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -33,7 +34,7 @@
 
   @Before
   public void setUp() {
-    fileSystem = new InMemoryFileSystem();
+    fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/shell/CommandUsingLinuxSandboxTest.java b/src/test/java/com/google/devtools/build/lib/shell/CommandUsingLinuxSandboxTest.java
index 2c8d2e4..47a2f45 100644
--- a/src/test/java/com/google/devtools/build/lib/shell/CommandUsingLinuxSandboxTest.java
+++ b/src/test/java/com/google/devtools/build/lib/shell/CommandUsingLinuxSandboxTest.java
@@ -43,7 +43,7 @@
 
   @Before
   public final void createFileSystem() throws Exception {
-    testFS = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    testFS = new UnixFileSystem(DigestHashFunction.SHA256);
     runfilesDir = testFS.getPath(BlazeTestUtils.runfilesDir());
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/shell/CommandUsingProcessWrapperTest.java b/src/test/java/com/google/devtools/build/lib/shell/CommandUsingProcessWrapperTest.java
index 90ea5bc..955137f 100644
--- a/src/test/java/com/google/devtools/build/lib/shell/CommandUsingProcessWrapperTest.java
+++ b/src/test/java/com/google/devtools/build/lib/shell/CommandUsingProcessWrapperTest.java
@@ -40,7 +40,7 @@
 
   @Before
   public final void createFileSystem() throws Exception {
-    testFS = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    testFS = new UnixFileSystem(DigestHashFunction.SHA256);
   }
 
   private ProcessWrapper getProcessWrapper() {
diff --git a/src/test/java/com/google/devtools/build/lib/shell/ExecutionStatisticsTest.java b/src/test/java/com/google/devtools/build/lib/shell/ExecutionStatisticsTest.java
index 6dcc571..d43807b 100644
--- a/src/test/java/com/google/devtools/build/lib/shell/ExecutionStatisticsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/shell/ExecutionStatisticsTest.java
@@ -37,7 +37,7 @@
 
   @Before
   public final void createFileSystem() throws Exception {
-    FileSystem testFS = new InMemoryFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem testFS = new InMemoryFileSystem(DigestHashFunction.SHA256);
     workingDir = testFS.getPath(TestUtils.makeTempDir().getCanonicalPath());
     workingDir.createDirectoryAndParents();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ASTFileLookupFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ASTFileLookupFunctionTest.java
index 7cdf93d..f0ede9b 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ASTFileLookupFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ASTFileLookupFunctionTest.java
@@ -25,6 +25,7 @@
 import com.google.devtools.build.lib.syntax.LoadStatement;
 import com.google.devtools.build.lib.syntax.StarlarkFile;
 import com.google.devtools.build.lib.syntax.Statement;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -44,9 +45,13 @@
 @RunWith(JUnit4.class)
 public class ASTFileLookupFunctionTest extends BuildViewTestCase {
 
-  private class MockFileSystem extends InMemoryFileSystem {
+  private static class MockFileSystem extends InMemoryFileSystem {
     PathFragment throwIOExceptionFor = null;
 
+    MockFileSystem() {
+      super(DigestHashFunction.SHA256);
+    }
+
     @Override
     public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
       if (throwIOExceptionFor != null && path.asFragment().equals(throwIOExceptionFor)) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/AbstractCollectPackagesUnderDirectoryTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/AbstractCollectPackagesUnderDirectoryTest.java
index 8866ae0..6dbdc76 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/AbstractCollectPackagesUnderDirectoryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/AbstractCollectPackagesUnderDirectoryTest.java
@@ -37,6 +37,7 @@
 import com.google.devtools.build.lib.testutil.TestPackageFactoryBuilderFactory;
 import com.google.devtools.build.lib.util.AbruptExitException;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -76,7 +77,7 @@
 
   @Before
   public void setUp() throws IOException {
-    fileSystem = new InMemoryFileSystem();
+    fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     workingDir = fileSystem.getPath(getWorkspacePathString());
     workingDir.createDirectoryAndParents();
     root = Root.fromPath(workingDir);
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java
index 0038aba..ee29fad 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java
@@ -38,6 +38,7 @@
 import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.Root;
@@ -58,7 +59,7 @@
 
   private final Scratch scratch =
       new Scratch(
-          new InMemoryFileSystem() {
+          new InMemoryFileSystem(DigestHashFunction.SHA256) {
             @Override
             public void chmod(Path path, int mode) throws IOException {
               assertThat(mode).isEqualTo(0555); // Read only and executable.
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTestCase.java b/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTestCase.java
index eaae5dc..5ba51a5 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTestCase.java
@@ -33,6 +33,7 @@
 import com.google.devtools.build.lib.testutil.TestRuleClassProvider;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Root;
@@ -174,6 +175,10 @@
 
   /** InMemoryFileSystem that can pretend to do a fast digest. */
   protected class CustomInMemoryFs extends InMemoryFileSystem {
+    CustomInMemoryFs() {
+      super(DigestHashFunction.SHA256);
+    }
+
     @Override
     protected byte[] getFastDigest(Path path) throws IOException {
       return fastDigest ? getDigest(path) : null;
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/BzlLoadFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/BzlLoadFunctionTest.java
index 2dfc450..c505229 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/BzlLoadFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/BzlLoadFunctionTest.java
@@ -31,6 +31,7 @@
 import com.google.devtools.build.lib.skyframe.BzlLoadFunction.BzlLoadFailedException;
 import com.google.devtools.build.lib.skyframe.util.SkyframeExecutorTestUtils;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -448,6 +449,10 @@
     @Nullable private Path badPathForStat;
     @Nullable private Path badPathForRead;
 
+    CustomInMemoryFs() {
+      super(DigestHashFunction.SHA256);
+    }
+
     @Override
     public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
       if (path.equals(badPathForStat)) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/DiffAwarenessManagerTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/DiffAwarenessManagerTest.java
index 8d76c90..8cd2ecb 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/DiffAwarenessManagerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/DiffAwarenessManagerTest.java
@@ -21,6 +21,7 @@
 import com.google.common.collect.Maps;
 import com.google.devtools.build.lib.events.util.EventCollectionApparatus;
 import com.google.devtools.build.lib.skyframe.DiffAwarenessManager.ProcessableModifiedFileSet;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -46,7 +47,7 @@
 
   @Before
   public final void createFileSystem() throws Exception  {
-    fs = new InMemoryFileSystem();
+    fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
   }
 
   @Before
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FileArtifactValueTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/FileArtifactValueTest.java
index 50783d1..04b2e11 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FileArtifactValueTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FileArtifactValueTest.java
@@ -22,6 +22,7 @@
 import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.util.Fingerprint;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -35,7 +36,7 @@
 @RunWith(JUnit4.class)
 public final class FileArtifactValueTest {
   private final ManualClock clock = new ManualClock();
-  private final FileSystem fs = new InMemoryFileSystem(clock);
+  private final FileSystem fs = new InMemoryFileSystem(clock, DigestHashFunction.SHA256);
 
   private Path scratchFile(String name, long mtime, String content) throws IOException {
     Path path = fs.getPath(name);
@@ -179,7 +180,7 @@
   public void testIOException() throws Exception {
     final IOException exception = new IOException("beep");
     FileSystem fs =
-        new InMemoryFileSystem() {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           public byte[] getDigest(Path path) throws IOException {
             throw exception;
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java
index ed89669..ae9168d 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FileFunctionTest.java
@@ -58,6 +58,7 @@
 import com.google.devtools.build.lib.testutil.TestRuleClassProvider;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileAccessException;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -1774,7 +1775,7 @@
     private final Map<Path, IOException> stubbedFastDigestErrors = Maps.newHashMap();
 
     CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock);
+      super(manualClock, DigestHashFunction.SHA256);
     }
 
     void stubFastDigestError(Path path, IOException error) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java
index 38bffd7..24835fe 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FileSymlinkCycleUniquenessFunctionTest.java
@@ -15,6 +15,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.testing.EqualsTester;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.RootedPath;
@@ -28,7 +29,7 @@
 
   @Test
   public void testHashCodeAndEqualsContract() throws Exception {
-    Root root = Root.fromPath(new InMemoryFileSystem().getPath("/root"));
+    Root root = Root.fromPath(new InMemoryFileSystem(DigestHashFunction.SHA256).getPath("/root"));
     RootedPath p1 = RootedPath.toRootedPath(root, PathFragment.create("p1"));
     RootedPath p2 = RootedPath.toRootedPath(root, PathFragment.create("p2"));
     RootedPath p3 = RootedPath.toRootedPath(root, PathFragment.create("p3"));
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTestBase.java b/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTestBase.java
index 09a1136..d92e3d2 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTestBase.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTestBase.java
@@ -25,6 +25,7 @@
 import com.google.devtools.build.lib.actions.util.ActionsTestUtil;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.testutil.ManualClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileStatusWithDigestAdapter;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -129,7 +130,7 @@
     }
 
     private MockFileSystem(ManualClock clock) {
-      super(clock);
+      super(clock, DigestHashFunction.SHA256);
     }
 
     @Override
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/GlobFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/GlobFunctionTest.java
index decb897..3f99311 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/GlobFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/GlobFunctionTest.java
@@ -43,6 +43,7 @@
 import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.testutil.TestConstants;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -809,7 +810,7 @@
     private Map<Path, FileStatus> stubbedStats = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock);
+      super(manualClock, DigestHashFunction.SHA256);
     }
 
     public void stubStat(Path path, @Nullable FileStatus stubbedResult) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java
index 1ae670a..c0837cb 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java
@@ -55,6 +55,7 @@
 import com.google.devtools.build.lib.util.ExitCode;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
@@ -1600,7 +1601,7 @@
     private final Map<Path, IOException> pathsToErrorOnGetInputStream = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock);
+      super(manualClock, DigestHashFunction.SHA256);
     }
 
     public void stubStat(Path path, @Nullable FileStatus stubbedResult) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ParallelBuilderTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ParallelBuilderTest.java
index a406dc5..2888e32 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ParallelBuilderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ParallelBuilderTest.java
@@ -49,6 +49,7 @@
 import com.google.devtools.build.lib.testutil.TestSpec;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.util.DetailedExitCode;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -247,59 +248,60 @@
   }
 
   @Test
-  public void testUpdateCacheError() throws Exception {
-    FileSystem fs = new InMemoryFileSystem() {
-      @Override
-      public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
-        final FileStatus stat = super.statIfFound(path, followSymlinks);
-        if (path.toString().endsWith("/out/foo")) {
-          return new FileStatus() {
-            private final FileStatus original = stat;
+  public void testUpdateCacheError() {
+    FileSystem fs =
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
+          @Override
+          public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
+            final FileStatus stat = super.statIfFound(path, followSymlinks);
+            if (path.toString().endsWith("/out/foo")) {
+              return new FileStatus() {
+                private final FileStatus original = stat;
 
-            @Override
-            public boolean isSymbolicLink() {
-              return original.isSymbolicLink();
-            }
+                @Override
+                public boolean isSymbolicLink() {
+                  return original.isSymbolicLink();
+                }
 
-            @Override
-            public boolean isFile() {
-              return original.isFile();
-            }
+                @Override
+                public boolean isFile() {
+                  return original.isFile();
+                }
 
-            @Override
-            public boolean isDirectory() {
-              return original.isDirectory();
-            }
+                @Override
+                public boolean isDirectory() {
+                  return original.isDirectory();
+                }
 
-            @Override
-            public boolean isSpecialFile() {
-              return original.isSpecialFile();
-            }
+                @Override
+                public boolean isSpecialFile() {
+                  return original.isSpecialFile();
+                }
 
-            @Override
-            public long getSize() throws IOException {
-              return original.getSize();
-            }
+                @Override
+                public long getSize() throws IOException {
+                  return original.getSize();
+                }
 
-            @Override
-            public long getNodeId() throws IOException {
-              return original.getNodeId();
-            }
+                @Override
+                public long getNodeId() throws IOException {
+                  return original.getNodeId();
+                }
 
-            @Override
-            public long getLastModifiedTime() throws IOException {
-              throw new IOException();
-            }
+                @Override
+                public long getLastModifiedTime() throws IOException {
+                  throw new IOException();
+                }
 
-            @Override
-            public long getLastChangeTime() throws IOException {
-              throw new IOException();
+                @Override
+                public long getLastChangeTime() throws IOException {
+                  throw new IOException();
+                }
+              };
             }
-          };
-        }
-        return stat;
-      }
-    };
+            return stat;
+          }
+        };
     Artifact foo = createDerivedArtifact(fs, "foo");
     registerAction(new TestAction(TestAction.NO_EFFECT, emptyNestedSet, ImmutableSet.of(foo)));
     reporter.removeHandler(failFastHandler);
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/SkyframeLabelVisitorTestCase.java b/src/test/java/com/google/devtools/build/lib/skyframe/SkyframeLabelVisitorTestCase.java
index 79056ce..f6e371d 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/SkyframeLabelVisitorTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/SkyframeLabelVisitorTestCase.java
@@ -35,6 +35,7 @@
 import com.google.devtools.build.lib.packages.util.PackageLoadingTestCase;
 import com.google.devtools.build.lib.pkgcache.TransitivePackageLoader;
 import com.google.devtools.build.lib.testutil.ManualClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
@@ -246,7 +247,7 @@
     private Map<Path, FileStatus> stubbedStats = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock);
+      super(manualClock, DigestHashFunction.SHA256);
     }
 
     public void stubStat(Path path, @Nullable FileStatus stubbedResult) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactBuildTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactBuildTest.java
index 5bc62ee..ccaf8f3 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactBuildTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactBuildTest.java
@@ -61,6 +61,7 @@
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.util.CrashFailureDetails;
 import com.google.devtools.build.lib.util.DetailedExitCode;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -580,12 +581,16 @@
             FileStatus stat = child1.getPath().stat(Symlinks.NOFOLLOW);
             FileArtifactValue metadata1 =
                 md.constructMetadataForDigest(
-                    child1, stat, Hashing.sha256().hashString("one", UTF_8).asBytes());
+                    child1,
+                    stat,
+                    DigestHashFunction.SHA256.getHashFunction().hashString("one", UTF_8).asBytes());
 
             stat = child2.getPath().stat(Symlinks.NOFOLLOW);
             FileArtifactValue metadata2 =
                 md.constructMetadataForDigest(
-                    child2, stat, Hashing.sha256().hashString("two", UTF_8).asBytes());
+                    child2,
+                    stat,
+                    DigestHashFunction.SHA256.getHashFunction().hashString("two", UTF_8).asBytes());
 
             // The metadata will not be equal to reading from the filesystem since the filesystem
             // won't have the digest. However, we should be able to detect that nothing could have
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactValueTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactValueTest.java
index 09ab04f..2de577f 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactValueTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/TreeArtifactValueTest.java
@@ -32,6 +32,7 @@
 import com.google.devtools.build.lib.skyframe.TreeArtifactValue.ArchivedRepresentation;
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.util.Pair;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -342,7 +343,7 @@
   @Test
   public void visitTree_throwsOnUnknownDirentType() {
     FileSystem fs =
-        new InMemoryFileSystem() {
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
           @Override
           public ImmutableList<Dirent> readdir(Path path, boolean followSymlinks) {
             return ImmutableList.of(new Dirent("?", Dirent.Type.UNKNOWN));
@@ -447,7 +448,8 @@
   public static final class MultiBuilderTest {
 
     private static final ArtifactRoot ROOT =
-        ArtifactRoot.asDerivedRoot(new InMemoryFileSystem().getPath("/root"), BIN_PATH);
+        ArtifactRoot.asDerivedRoot(
+            new InMemoryFileSystem(DigestHashFunction.SHA256).getPath("/root"), BIN_PATH);
 
     private enum MultiBuilderType {
       BASIC {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoaderTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoaderTest.java
index 2745151..f082350 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoaderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoaderTest.java
@@ -28,6 +28,7 @@
 import com.google.devtools.build.lib.packages.NoSuchPackageException;
 import com.google.devtools.build.lib.packages.Package;
 import com.google.devtools.build.lib.skyframe.ExternalFilesHelper.ExternalFileAction;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -48,7 +49,7 @@
 
   @Before
   public final void init() throws Exception {
-    fs = new InMemoryFileSystem();
+    fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     workspaceDir = fs.getPath("/workspace/");
     workspaceDir.createDirectoryAndParents();
     root = Root.fromPath(workspaceDir);
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java b/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java
index 7c35a5c..e2191ea 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java
@@ -22,6 +22,7 @@
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.events.EventKind;
 import com.google.devtools.build.lib.events.Reporter;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Root;
@@ -98,7 +99,7 @@
    * Creates the file system; override to inject FS behavior.
    */
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance());
+    return new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
   }
 
   // Mix-in assertions:
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/Scratch.java b/src/test/java/com/google/devtools/build/lib/testutil/Scratch.java
index bf2621a..60e3b8e 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/Scratch.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/Scratch.java
@@ -16,6 +16,7 @@
 
 import com.google.common.io.ByteStreams;
 import com.google.devtools.build.lib.clock.BlazeClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -41,14 +42,14 @@
    * Create a new ScratchFileSystem using the {@link InMemoryFileSystem}
    */
   public Scratch() {
-    this(new InMemoryFileSystem(BlazeClock.instance()), "/");
+    this(new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256), "/");
   }
 
   /**
    * Create a new ScratchFileSystem using the {@link InMemoryFileSystem}
    */
   public Scratch(String workingDir) {
-    this(new InMemoryFileSystem(BlazeClock.instance()), workingDir);
+    this(new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256), workingDir);
   }
 
   /**
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/TestFileOutErr.java b/src/test/java/com/google/devtools/build/lib/testutil/TestFileOutErr.java
index fb912c5..830f31d 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/TestFileOutErr.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/TestFileOutErr.java
@@ -14,6 +14,7 @@
 package com.google.devtools.build.lib.testutil;
 
 import com.google.devtools.build.lib.util.io.FileOutErr;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -38,7 +39,7 @@
   }
 
   private static Path newInMemoryFile(File root, String name) {
-    InMemoryFileSystem inMemFS = new InMemoryFileSystem();
+    InMemoryFileSystem inMemFS = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path directory = inMemFS.getPath(root.getPath());
     try {
       FileSystemUtils.createDirectoryAndParents(directory);
diff --git a/src/test/java/com/google/devtools/build/lib/unix/NativePosixFilesTest.java b/src/test/java/com/google/devtools/build/lib/unix/NativePosixFilesTest.java
index 7fc0c6a..fd9f2c7 100644
--- a/src/test/java/com/google/devtools/build/lib/unix/NativePosixFilesTest.java
+++ b/src/test/java/com/google/devtools/build/lib/unix/NativePosixFilesTest.java
@@ -42,7 +42,7 @@
 
   @Before
   public final void createFileSystem() throws Exception  {
-    testFS = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    testFS = new UnixFileSystem(DigestHashFunction.SHA256);
     workingDir = testFS.getPath(new File(TestUtils.tmpDir()).getCanonicalPath());
     testFile = workingDir.getRelative("test");
   }
diff --git a/src/test/java/com/google/devtools/build/lib/unix/UnixPathEqualityTest.java b/src/test/java/com/google/devtools/build/lib/unix/UnixPathEqualityTest.java
index 7a7690e..7f3cb92 100644
--- a/src/test/java/com/google/devtools/build/lib/unix/UnixPathEqualityTest.java
+++ b/src/test/java/com/google/devtools/build/lib/unix/UnixPathEqualityTest.java
@@ -37,8 +37,8 @@
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    unixFs = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
-    otherUnixFs = new UnixFileSystem(DigestHashFunction.getDefaultUnchecked());
+    unixFs = new UnixFileSystem(DigestHashFunction.SHA256);
+    otherUnixFs = new UnixFileSystem(DigestHashFunction.SHA256);
     assertThat(unixFs != otherUnixFs).isTrue();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/util/DependencySetWindowsTest.java b/src/test/java/com/google/devtools/build/lib/util/DependencySetWindowsTest.java
index a519598..74e0bd7 100644
--- a/src/test/java/com/google/devtools/build/lib/util/DependencySetWindowsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/DependencySetWindowsTest.java
@@ -31,8 +31,7 @@
 
   private Scratch scratch = new Scratch();
   private final FileSystem fileSystem =
-      new WindowsFileSystem(
-          DigestHashFunction.getDefaultUnchecked(), /*createSymbolicLinks=*/ false);
+      new WindowsFileSystem(DigestHashFunction.SHA256, /*createSymbolicLinks=*/ false);
   private final Path root = fileSystem.getPath("C:/");
 
   private DependencySet newDependencySet() {
diff --git a/src/test/java/com/google/devtools/build/lib/util/FileTypeTest.java b/src/test/java/com/google/devtools/build/lib/util/FileTypeTest.java
index 9662ca5..0cf7562 100644
--- a/src/test/java/com/google/devtools/build/lib/util/FileTypeTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/FileTypeTest.java
@@ -19,6 +19,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
 import com.google.devtools.build.lib.util.FileType.HasFileType;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -83,7 +84,7 @@
 
   @Test
   public void handlesPathObjects() {
-    Path readme = new InMemoryFileSystem().getPath("/readme.txt");
+    Path readme = new InMemoryFileSystem(DigestHashFunction.SHA256).getPath("/readme.txt");
     assertThat(TEXT.matches(readme)).isTrue();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java b/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java
index bac5369..bcba45b 100644
--- a/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/FingerprintTest.java
@@ -18,6 +18,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.clock.BlazeClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -122,7 +123,7 @@
     PathFragment pf = PathFragment.create("/etc/pwd");
     assertThat(new Fingerprint().addPath(pf).hexDigestAndReset())
         .isEqualTo("0b229115c2da46773ff38528420b922488dd564ddb3c0c861fb1c77ae8525f9b");
-    Path p = new InMemoryFileSystem(BlazeClock.instance()).getPath(pf);
+    Path p = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256).getPath(pf);
     assertThat(new Fingerprint().addPath(p).hexDigestAndReset())
         .isEqualTo("0b229115c2da46773ff38528420b922488dd564ddb3c0c861fb1c77ae8525f9b");
   }
diff --git a/src/test/java/com/google/devtools/build/lib/util/io/AsynchronousFileOutputStreamTest.java b/src/test/java/com/google/devtools/build/lib/util/io/AsynchronousFileOutputStreamTest.java
index 80685a5..1a7381e 100644
--- a/src/test/java/com/google/devtools/build/lib/util/io/AsynchronousFileOutputStreamTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/io/AsynchronousFileOutputStreamTest.java
@@ -18,6 +18,7 @@
 
 import com.google.common.io.ByteStreams;
 import com.google.devtools.build.lib.runtime.commands.proto.BazelFlagsProto.FlagInfo;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -78,7 +79,7 @@
 
   @Test
   public void testConcurrentWrites() throws Exception {
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path logPath = fileSystem.getPath("/logFile");
     AsynchronousFileOutputStream out = new AsynchronousFileOutputStream(logPath);
     Thread[] writers = new Thread[10];
@@ -118,7 +119,7 @@
   @Test
   public void testConcurrentProtoWrites() throws Exception {
     final String filename = "/logFile";
-    FileSystem fileSystem = new InMemoryFileSystem();
+    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path logPath = fileSystem.getPath(filename);
     AsynchronousFileOutputStream out = new AsynchronousFileOutputStream(logPath);
     ArrayList<FlagInfo> messages = new ArrayList<>();
diff --git a/src/test/java/com/google/devtools/build/lib/versioning/GnuVersionParserTest.java b/src/test/java/com/google/devtools/build/lib/versioning/GnuVersionParserTest.java
index abc5ba5..8f1829f 100644
--- a/src/test/java/com/google/devtools/build/lib/versioning/GnuVersionParserTest.java
+++ b/src/test/java/com/google/devtools/build/lib/versioning/GnuVersionParserTest.java
@@ -94,7 +94,7 @@
 
   /** Creates an executable shell script with the given contents and returns its path. */
   private static Path createHelper(String content) throws IOException {
-    FileSystem fs = new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked());
+    FileSystem fs = new JavaIoFileSystem(DigestHashFunction.SHA256);
     Path helper = fs.getPath(System.getenv("TEST_TMPDIR")).getRelative("helper.sh");
     try (PrintWriter output =
         new PrintWriter(new OutputStreamWriter(helper.getOutputStream(), StandardCharsets.UTF_8))) {
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/FileSystemUtilsTest.java b/src/test/java/com/google/devtools/build/lib/vfs/FileSystemUtilsTest.java
index 765f63f..88e9a7d 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/FileSystemUtilsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/FileSystemUtilsTest.java
@@ -54,7 +54,7 @@
   @Before
   public final void initializeFileSystem() throws Exception  {
     clock = new ManualClock();
-    fileSystem = new InMemoryFileSystem(clock);
+    fileSystem = new InMemoryFileSystem(clock, DigestHashFunction.SHA256);
     workingDir = fileSystem.getPath("/workingDir");
     workingDir.createDirectory();
   }
@@ -365,6 +365,10 @@
   @Test
   public void testMoveFileAcrossDevices() throws Exception {
     class MultipleDeviceFS extends InMemoryFileSystem {
+      MultipleDeviceFS() {
+        super(DigestHashFunction.SHA256);
+      }
+
       @Override
       public void renameTo(Path source, Path target) throws IOException {
         if (!source.startsWith(target.asFragment().subFragment(0, 1))) {
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/GlobTest.java b/src/test/java/com/google/devtools/build/lib/vfs/GlobTest.java
index be3fded..e9bf357 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/GlobTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/GlobTest.java
@@ -56,23 +56,24 @@
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    fs = new InMemoryFileSystem() {
-      @Override
-      public Collection<Dirent> readdir(Path path, boolean followSymlinks) throws IOException {
-        if (path.equals(throwOnReaddir)) {
-          throw new FileNotFoundException(path.getPathString());
-        }
-        return super.readdir(path, followSymlinks);
-      }
+    fs =
+        new InMemoryFileSystem(DigestHashFunction.SHA256) {
+          @Override
+          public Collection<Dirent> readdir(Path path, boolean followSymlinks) throws IOException {
+            if (path.equals(throwOnReaddir)) {
+              throw new FileNotFoundException(path.getPathString());
+            }
+            return super.readdir(path, followSymlinks);
+          }
 
-      @Override
-      public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
-        if (path.equals(throwOnStat)) {
-          throw new FileNotFoundException(path.getPathString());
-        }
-        return super.statIfFound(path, followSymlinks);
-      }
-    };
+          @Override
+          public FileStatus statIfFound(Path path, boolean followSymlinks) throws IOException {
+            if (path.equals(throwOnStat)) {
+              throw new FileNotFoundException(path.getPathString());
+            }
+            return super.statIfFound(path, followSymlinks);
+          }
+        };
     tmpPath = fs.getPath("/globtmp");
     for (String dir : ImmutableList.of("foo/bar/wiz",
                          "foo/barnacle/wiz",
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/PathAbstractTest.java b/src/test/java/com/google/devtools/build/lib/vfs/PathAbstractTest.java
index a328f88..a52a592f 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/PathAbstractTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/PathAbstractTest.java
@@ -37,7 +37,7 @@
 
   @Before
   public void setup() {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     isCaseSensitive = OsPathPolicy.getFilePathOs().isCaseSensitive();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java b/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java
index 3440e83..763d2b4 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/PathFragmentTest.java
@@ -43,7 +43,7 @@
 
   @Test
   public void testEqualsAndHashCode() {
-    InMemoryFileSystem filesystem = new InMemoryFileSystem();
+    InMemoryFileSystem filesystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
     new EqualsTester()
         .addEqualityGroup(
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/RecursiveGlobTest.java b/src/test/java/com/google/devtools/build/lib/vfs/RecursiveGlobTest.java
index 4d36929..1c2ac8a 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/RecursiveGlobTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/RecursiveGlobTest.java
@@ -37,7 +37,7 @@
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     tmpPath = fileSystem.getPath("/rglobtmp");
     for (String dir : ImmutableList.of("foo/bar/wiz",
                          "foo/baz/wiz",
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/RootTest.java b/src/test/java/com/google/devtools/build/lib/vfs/RootTest.java
index b06215e..4dfabeb 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/RootTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/RootTest.java
@@ -39,12 +39,12 @@
 
   @Before
   public final void initializeFileSystem() throws Exception {
-    fs = new InMemoryFileSystem(BlazeClock.instance());
+    fs = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
   }
 
   @Test
   public void testEqualsAndHashCodeContract() throws Exception {
-    FileSystem otherFs = new InMemoryFileSystem(BlazeClock.instance());
+    FileSystem otherFs = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     new EqualsTester()
         .addEqualityGroup(Root.absoluteRoot(fs), Root.absoluteRoot(fs))
         .addEqualityGroup(Root.absoluteRoot(otherFs), Root.absoluteRoot(otherFs))
@@ -71,7 +71,7 @@
 
   @Test
   public void testFilesystemTransform() throws Exception {
-    FileSystem fs2 = new InMemoryFileSystem(BlazeClock.instance());
+    FileSystem fs2 = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     Root root = Root.fromPath(fs.getPath("/foo"));
     Root root2 = Root.toFileSystem(root, fs2);
     assertThat(root2.asPath().getFileSystem()).isSameInstanceAs(fs2);
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/RootedPathAndCasingTest.java b/src/test/java/com/google/devtools/build/lib/vfs/RootedPathAndCasingTest.java
index b73e450..48414fc 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/RootedPathAndCasingTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/RootedPathAndCasingTest.java
@@ -24,7 +24,8 @@
 /** Tests for {@link RootedPathAndCasing}. */
 @RunWith(JUnit4.class)
 public class RootedPathAndCasingTest {
-  private final Path root = new InMemoryFileSystem(BlazeClock.instance()).getPath("c:/");
+  private final Path root =
+      new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256).getPath("c:/");
 
   @Test
   public void testSanityCheckFilesystemIsCaseInsensitive() {
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/RootedPathTest.java b/src/test/java/com/google/devtools/build/lib/vfs/RootedPathTest.java
index b23b4a7..5b216fb 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/RootedPathTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/RootedPathTest.java
@@ -33,7 +33,7 @@
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    filesystem = new InMemoryFileSystem(BlazeClock.instance());
+    filesystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     root = filesystem.getPath("/");
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/SearchPathTest.java b/src/test/java/com/google/devtools/build/lib/vfs/SearchPathTest.java
index e815a8c..46c1c14 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/SearchPathTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/SearchPathTest.java
@@ -25,7 +25,7 @@
 
 @RunWith(JUnit4.class)
 public class SearchPathTest {
-  private FileSystem fs = new InMemoryFileSystem();
+  private FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   @Test
   public void testNull() throws Exception {
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/util/FileSystems.java b/src/test/java/com/google/devtools/build/lib/vfs/util/FileSystems.java
index c4778eb..c875b91 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/util/FileSystems.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/util/FileSystems.java
@@ -43,6 +43,6 @@
 
   /** Constructs a java.io.File file system. */
   public static FileSystem getJavaIoFileSystem() {
-    return new JavaIoFileSystem(DigestHashFunction.getDefaultUnchecked());
+    return new JavaIoFileSystem(DigestHashFunction.SHA256);
   }
 }
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/util/FsApparatus.java b/src/test/java/com/google/devtools/build/lib/vfs/util/FsApparatus.java
index 7c765fa..09ae044 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/util/FsApparatus.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/util/FsApparatus.java
@@ -16,6 +16,7 @@
 import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.testutil.TestUtils;
 import com.google.devtools.build.lib.util.StringUtilities;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -68,7 +69,7 @@
   }
 
   private FsApparatus() {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     workingDir = fileSystem.getPath("/");
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/windows/WindowsFileSystemTest.java b/src/test/java/com/google/devtools/build/lib/windows/WindowsFileSystemTest.java
index c44fca0..7f64469 100644
--- a/src/test/java/com/google/devtools/build/lib/windows/WindowsFileSystemTest.java
+++ b/src/test/java/com/google/devtools/build/lib/windows/WindowsFileSystemTest.java
@@ -51,9 +51,7 @@
 
   @Before
   public void loadJni() throws Exception {
-    fs =
-        new WindowsFileSystem(
-            DigestHashFunction.getDefaultUnchecked(), /*createSymbolicLinks=*/ false);
+    fs = new WindowsFileSystem(DigestHashFunction.SHA256, /*createSymbolicLinks=*/ false);
     scratchRoot = fs.getPath(System.getenv("TEST_TMPDIR")).getRelative("x");
     testUtil = new WindowsTestUtil(scratchRoot.getPathString());
     cleanupScratchDir();
@@ -336,9 +334,7 @@
 
   @Test
   public void testCreateSymbolicLinkWithRealSymlinks() throws Exception {
-    fs =
-        new WindowsFileSystem(
-            DigestHashFunction.getDefaultUnchecked(), /*createSymbolicLinks=*/ true);
+    fs = new WindowsFileSystem(DigestHashFunction.SHA256, /*createSymbolicLinks=*/ true);
     java.nio.file.Path helloPath = testUtil.scratchFile("hello.txt", "hello");
     PathFragment targetFragment = PathFragment.create(helloPath.toString());
     Path linkPath = scratchRoot.getRelative("link.txt");
diff --git a/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java b/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java
index 47db078..04077da 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/ErrorMessageTest.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -84,7 +85,7 @@
 
   @Test
   public void testErrorMessageWithLogFile() throws Exception {
-    InMemoryFileSystem fs = new InMemoryFileSystem();
+    InMemoryFileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     Path logFile = fs.getPath("/log.txt");
     FileSystemUtils.writeContent(logFile, UTF_8, logText);
     ErrorMessage errorMessage =
@@ -99,7 +100,7 @@
 
   @Test
   public void testErrorMessageWithUnreadableLogFile() {
-    InMemoryFileSystem fs = new InMemoryFileSystem();
+    InMemoryFileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
     // This file does not exist.
     Path logFile = fs.getPath("/nope.txt");
     ErrorMessage errorMessage =
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerExecRootTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerExecRootTest.java
index 3a61adf..0217f1b 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerExecRootTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerExecRootTest.java
@@ -20,6 +20,7 @@
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxInputs;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxOutputs;
 import com.google.devtools.build.lib.testutil.TestUtils;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -44,7 +45,7 @@
 
   @Before
   public final void setupTestDirs() throws IOException {
-    fileSystem = new InMemoryFileSystem();
+    fileSystem = new InMemoryFileSystem(DigestHashFunction.SHA256);
     testRoot = fileSystem.getPath(TestUtils.tmpDir());
     testRoot.createDirectoryAndParents();
 
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerFactoryTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerFactoryTest.java
index 96a146e..4407d47 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerFactoryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerFactoryTest.java
@@ -20,6 +20,7 @@
 import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.hash.HashCode;
 import com.google.devtools.build.lib.actions.ExecutionRequirements.WorkerProtocolFormat;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -31,7 +32,7 @@
 @RunWith(JUnit4.class)
 public class WorkerFactoryTest {
 
-  final FileSystem fs = new InMemoryFileSystem();
+  final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   /**
    * Regression test for b/64689608: The execroot of the sandboxed worker process must end with the
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerKeyTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerKeyTest.java
index c477f68..0fa2221 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerKeyTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerKeyTest.java
@@ -21,6 +21,7 @@
 import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.hash.HashCode;
 import com.google.devtools.build.lib.actions.ExecutionRequirements.WorkerProtocolFormat;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -31,7 +32,7 @@
 /** Tests for {@link WorkerKey}. */
 @RunWith(JUnit4.class)
 public class WorkerKeyTest {
-  final FileSystem fs = new InMemoryFileSystem();
+  final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   Path workerBaseDir = fs.getPath("/outputbase/bazel-workers");
   WorkerKey workerKey =
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerMultiplexerManagerTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerMultiplexerManagerTest.java
index c13f978..8e9c027 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerMultiplexerManagerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerMultiplexerManagerTest.java
@@ -24,6 +24,7 @@
 import com.google.devtools.build.lib.actions.ExecutionRequirements.WorkerProtocolFormat;
 import com.google.devtools.build.lib.actions.UserExecException;
 import com.google.devtools.build.lib.clock.BlazeClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -40,7 +41,7 @@
 
   @Before
   public void setUp() {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     WorkerMultiplexerManager.reset();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerPoolTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerPoolTest.java
index b0ad184..fd82c58 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerPoolTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerPoolTest.java
@@ -26,6 +26,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.google.devtools.build.lib.clock.BlazeClock;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -57,7 +58,7 @@
 
   @Before
   public void setUp() throws Exception {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.SHA256);
     doAnswer(
             arg -> {
               return new DefaultPooledObject<>(
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerSpawnRunnerTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerSpawnRunnerTest.java
index b165c45..0192e7f 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerSpawnRunnerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerSpawnRunnerTest.java
@@ -36,6 +36,7 @@
 import com.google.devtools.build.lib.sandbox.SandboxHelpers;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxInputs;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxOutputs;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -55,7 +56,7 @@
 /** Unit tests for the WorkerSpawnRunner. */
 @RunWith(JUnit4.class)
 public class WorkerSpawnRunnerTest {
-  final FileSystem fs = new InMemoryFileSystem();
+  final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
   @Rule public final MockitoRule mockito = MockitoJUnit.rule();
   @Mock ExtendedEventHandler reporter;
   @Mock LocalEnvProvider localEnvProvider;
diff --git a/src/test/java/com/google/devtools/build/lib/worker/WorkerTest.java b/src/test/java/com/google/devtools/build/lib/worker/WorkerTest.java
index 716d185..f380730 100644
--- a/src/test/java/com/google/devtools/build/lib/worker/WorkerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/worker/WorkerTest.java
@@ -29,6 +29,7 @@
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxInputs;
 import com.google.devtools.build.lib.sandbox.SandboxHelpers.SandboxOutputs;
 import com.google.devtools.build.lib.shell.Subprocess;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -50,7 +51,7 @@
 /** Tests for {@link Worker}. */
 @RunWith(JUnit4.class)
 public final class WorkerTest {
-  final FileSystem fs = new InMemoryFileSystem();
+  final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.SHA256);
 
   /** A worker that uses a fake subprocess for I/O. */
   private static class TestWorker extends Worker {