src/test/java/com/google/devtools/build/lib/buildtool/TargetCompleteEventTest.java - bazel - Git at Google

 // Copyright 2021 The Bazel Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //    http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 package com.google.devtools.build.lib.buildtool;

 import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;

 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.eventbus.Subscribe;
 import com.google.common.hash.HashCode;
 import com.google.common.io.BaseEncoding;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.OutputGroupInfo;
 import com.google.devtools.build.lib.analysis.TargetCompleteEvent;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
 import com.google.devtools.build.lib.analysis.util.AnalysisMock;
 import com.google.devtools.build.lib.authandtls.credentialhelper.CredentialModule;
 import com.google.devtools.build.lib.buildeventservice.BazelBuildEventServiceModule;
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos;
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEvent;
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEventId.IdCase;
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.NamedSetOfFiles;
 import com.google.devtools.build.lib.buildtool.util.BuildIntegrationTestCase;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.runtime.BlazeRuntime;
 import com.google.devtools.build.lib.runtime.NoSpawnCacheModule;
 import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.Nullable;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;

 /** Verifies TargetCompleteEvent behavior during a complete build. */
 @RunWith(JUnit4.class)
 public final class TargetCompleteEventTest extends BuildIntegrationTestCase {

   @Rule public final TemporaryFolder tmpFolder = new TemporaryFolder();

   @Before
   public void stageEmbeddedTools() throws Exception {
     AnalysisMock.get().setupMockToolsRepository(mockToolsConfig);
   }

   @Override
   protected BlazeRuntime.Builder getRuntimeBuilder() throws Exception {
     return super.getRuntimeBuilder()
         .addBlazeModule(new NoSpawnCacheModule())
         .addBlazeModule(new CredentialModule())
         .addBlazeModule(new BazelBuildEventServiceModule());
   }

   private void afterBuildCommand() throws Exception {
     runtimeWrapper.newCommand();
   }

   /**
    * Validates that TargetCompleteEvents do not keep a map of action output metadata for the
    * _validation output group, which can be quite large.
    */
   @Test
   public void artifactsNotRetained() throws Exception {
     write(
         "validation_actions/defs.bzl",
         "def _rule_with_implicit_outs_and_validation_impl(ctx):",
         "",
         "  ctx.actions.write(ctx.outputs.main, \"main output\\n\")",
         "",
         "  ctx.actions.write(ctx.outputs.implicit, \"implicit output\\n\")",
         "",
         "  validation_output = ctx.actions.declare_file(ctx.attr.name + \".validation\")",
         "  # The actual tool will be created in individual tests, depending on whether",
         "  # validation should pass or fail.",
         "  ctx.actions.run(",
         "      outputs = [validation_output],",
         "      executable = ctx.executable._validation_tool,",
         "      arguments = [validation_output.path])",
         "",
         "  return [",
         "    DefaultInfo(files = depset([ctx.outputs.main])),",
         "    OutputGroupInfo(_validation = depset([validation_output])),",
         "  ]",
         "",
         "",
         "rule_with_implicit_outs_and_validation = rule(",
         "  implementation = _rule_with_implicit_outs_and_validation_impl,",
         "  outputs = {",
         "    \"main\": \"%{name}.main\",",
         "    \"implicit\": \"%{name}.implicit\",",
         "  },",
         "  attrs = {",
         "    \"_validation_tool\": attr.label(",
         "        allow_single_file = True,",
         "        default = Label(\"//validation_actions:validation_tool\"),",
         "        executable = True,",
         "        cfg = \"exec\"),",
         "  }",
         ")");
     write("validation_actions/validation_tool", "#!/bin/bash", "echo \"validation output\" > $1")
         .setExecutable(true);
     write(
         "validation_actions/BUILD",
         "load(",
         "    \":defs.bzl\",",
         "    \"rule_with_implicit_outs_and_validation\")",
         "",
         "rule_with_implicit_outs_and_validation(name = \"foo0\")");

     AtomicReference<TargetCompleteEvent> targetCompleteEventRef = new AtomicReference<>();
     runtimeWrapper.registerSubscriber(
         new Object() {
           @SuppressWarnings("unused")
           @Subscribe
           public void accept(TargetCompleteEvent event) {
             targetCompleteEventRef.set(event);
           }
         });

     addOptions("--experimental_run_validations");
     BuildResult buildResult = buildTarget("//validation_actions:foo0");

     Collection<ConfiguredTarget> successfulTargets = buildResult.getSuccessfulTargets();
     ConfiguredTarget fooTarget = Iterables.getOnlyElement(successfulTargets);

     // Check that the primary output, :foo0.main, has its metadata retained.
     Artifact main =
         ((RuleConfiguredTarget) fooTarget)
             .findArtifactByOutputLabel(
                 Label.parseCanonicalUnchecked("//validation_actions:foo0.main"));
     FileArtifactValue mainMetadata =
         targetCompleteEventRef.get().getCompletionContext().getFileArtifactValue(main);
     assertThat(mainMetadata).isNotNull();

     // Check that the validation output, :foo0.validation, does not have its metadata retained.
     OutputGroupInfo outputGroups = fooTarget.get(OutputGroupInfo.STARLARK_CONSTRUCTOR);
     NestedSet<Artifact> validationArtifacts =
         outputGroups.getOutputGroup(OutputGroupInfo.VALIDATION);
     assertThat(validationArtifacts.isEmpty()).isFalse();

     Artifact validationArtifact = Iterables.getOnlyElement(validationArtifacts.toList());

     FileArtifactValue validationArtifactMetadata =
         targetCompleteEventRef
             .get()
             .getCompletionContext()
             .getFileArtifactValue(validationArtifact);
     assertThat(validationArtifactMetadata).isNull();
   }

   @Test
   public void outputFile() throws Exception {
     write("foo/BUILD", "genrule(name = 'foobin', outs = ['out.txt'], cmd = 'echo -n Hello > $@')");

     File bep = buildTargetAndCaptureBEP("//foo:foobin");

     BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(bep, "out.txt");
     assertThat(outFile).isNotNull();
     assertThat(outFile.getUri()).startsWith("file://");
     assertThat(outFile.getUri()).endsWith("/bin/foo/out.txt");
     assertThat(outFile.getLength()).isEqualTo("Hello".length());
     assertDigest("Hello", BaseEncoding.base16().lowerCase().decode(outFile.getDigest()));
   }

   @Test
   public void outputDirectory() throws Exception {
     write(
         "foo/defs.bzl",
         "def _impl(ctx):",
         "  dir = ctx.actions.declare_directory(ctx.label.name)",
         "  ctx.actions.run_shell(",
         "    outputs = [dir],",
         "    command = 'echo -n Hello > %s/file.txt' % dir.path,",
         ")",
         "  return DefaultInfo(files = depset([dir]))",
         "",
         "directory = rule(implementation = _impl)");
     write("foo/BUILD", "load(':defs.bzl', 'directory')", "directory(name = 'dir')");

     File bep = buildTargetAndCaptureBEP("//foo:dir");

     BuildEventStreamProtos.TargetComplete targetComplete = findTargetCompleteEventInBEPStream(bep);
     assertThat(targetComplete.getDirectoryOutputList()).hasSize(1);
     BuildEventStreamProtos.File dir = targetComplete.getDirectoryOutputList().get(0);
     assertThat(dir.getName()).endsWith("/dir");
     assertThat(dir.getUri()).isEmpty();
     assertThat(dir.getContents()).isEmpty();
     assertThat(dir.getSymlinkTargetPath()).isEmpty();

     BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(bep, "file.txt");
     assertThat(outFile).isNotNull();
     assertThat(outFile.getUri()).startsWith("file://");
     assertThat(outFile.getUri()).endsWith("/bin/foo/dir/file.txt");
     assertThat(outFile.getLength()).isEqualTo("Hello".length());
     assertDigest("Hello", BaseEncoding.base16().lowerCase().decode(outFile.getDigest()));
   }

   @Test
   public void outputSymlink() throws Exception {
     write(
         "foo/defs.bzl",
         "def _impl(ctx):",
         "  sym = ctx.actions.declare_symlink(ctx.label.name)",
         "  ctx.actions.symlink(output = sym, target_path = '/some/path')",
         "  return DefaultInfo(files = depset([sym]))",
         "",
         "symlink = rule(implementation = _impl)");
     write("foo/BUILD", "load(':defs.bzl', 'symlink')", "symlink(name = 'sym')");

     File bep = buildTargetAndCaptureBEP("//foo:sym");

     BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(bep, "sym");
     assertThat(outFile).isNotNull();
     assertThat(outFile.getSymlinkTargetPath()).isEqualTo("/some/path");
     assertThat(outFile.getLength()).isEqualTo(0);
     assertThat(outFile.getDigest()).isEmpty();
   }

   private File buildTargetAndCaptureBEP(String target) throws Exception {
     File bep = tmpFolder.newFile();
     // We use WAIT_FOR_UPLOAD_COMPLETE because it's the easiest way to force the BES module to
     // wait until the BEP binary file has been written.
     addOptions(
         "--build_event_binary_file=" + bep.getAbsolutePath(),
         "--bes_upload_mode=WAIT_FOR_UPLOAD_COMPLETE");
     buildTarget(target);
     // We need to wait for all events to be written to the file, which is done in #afterCommand()
     // if --bes_upload_mode=WAIT_FOR_UPLOAD_COMPLETE.
     afterBuildCommand();
     return bep;
   }

   private static void assertDigest(String contents, byte[] bepDigest) {
     // Try all registered hash functions and verify that one of them was used to produce the digest.
     boolean foundHashFunction = false;
     for (DigestHashFunction hashFunction : DigestHashFunction.getPossibleHashFunctions()) {
       HashCode hashCode = hashFunction.getHashFunction().hashString(contents, UTF_8);
       if (Arrays.equals(bepDigest, hashCode.asBytes())) {
         foundHashFunction = true;
       }
     }
     assertThat(foundHashFunction).isTrue();
   }

   private static ImmutableList<BuildEvent> parseBuildEventsFromBEPStream(File bep)
       throws IOException {
     ImmutableList.Builder<BuildEvent> buildEvents = ImmutableList.builder();
     try (InputStream in = new FileInputStream(bep)) {
       while (in.available() > 0) {
         buildEvents.add(BuildEvent.parseDelimitedFrom(in));
       }
     }
     return buildEvents.build();
   }

   @Nullable
   private static BuildEventStreamProtos.TargetComplete findTargetCompleteEventInBEPStream(File bep)
       throws IOException {
     for (BuildEvent buildEvent : parseBuildEventsFromBEPStream(bep)) {
       if (buildEvent.getId().getIdCase() == IdCase.TARGET_COMPLETED) {
         return buildEvent.getCompleted();
       }
     }
     return null;
   }

   @Nullable
   private static BuildEventStreamProtos.File findOutputFileInBEPStream(File bep, String name)
       throws IOException {
     for (BuildEvent buildEvent : parseBuildEventsFromBEPStream(bep)) {
       if (buildEvent.getId().getIdCase() == IdCase.NAMED_SET) {
         NamedSetOfFiles namedSetOfFiles = buildEvent.getNamedSetOfFiles();
         for (BuildEventStreamProtos.File file : namedSetOfFiles.getFilesList()) {
           if (file.getName().contains(name)) {
             return file;
           }
         }
       }
     }
     return null;
   }
 }
	// Copyright 2021 The Bazel Authors. All rights reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	package com.google.devtools.build.lib.buildtool;

	import static com.google.common.truth.Truth.assertThat;
	import static java.nio.charset.StandardCharsets.UTF_8;

	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.Iterables;
	import com.google.common.eventbus.Subscribe;
	import com.google.common.hash.HashCode;
	import com.google.common.io.BaseEncoding;
	import com.google.devtools.build.lib.actions.Artifact;
	import com.google.devtools.build.lib.actions.FileArtifactValue;
	import com.google.devtools.build.lib.analysis.ConfiguredTarget;
	import com.google.devtools.build.lib.analysis.OutputGroupInfo;
	import com.google.devtools.build.lib.analysis.TargetCompleteEvent;
	import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
	import com.google.devtools.build.lib.analysis.util.AnalysisMock;
	import com.google.devtools.build.lib.authandtls.credentialhelper.CredentialModule;
	import com.google.devtools.build.lib.buildeventservice.BazelBuildEventServiceModule;
	import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos;
	import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEvent;
	import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEventId.IdCase;
	import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.NamedSetOfFiles;
	import com.google.devtools.build.lib.buildtool.util.BuildIntegrationTestCase;
	import com.google.devtools.build.lib.cmdline.Label;
	import com.google.devtools.build.lib.collect.nestedset.NestedSet;
	import com.google.devtools.build.lib.runtime.BlazeRuntime;
	import com.google.devtools.build.lib.runtime.NoSpawnCacheModule;
	import com.google.devtools.build.lib.vfs.DigestHashFunction;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.concurrent.atomic.AtomicReference;
	import javax.annotation.Nullable;
	import org.junit.Before;
	import org.junit.Rule;
	import org.junit.Test;
	import org.junit.rules.TemporaryFolder;
	import org.junit.runner.RunWith;
	import org.junit.runners.JUnit4;

	/** Verifies TargetCompleteEvent behavior during a complete build. */
	@RunWith(JUnit4.class)
	public final class TargetCompleteEventTest extends BuildIntegrationTestCase {

	@Rule public final TemporaryFolder tmpFolder = new TemporaryFolder();

	@Before
	public void stageEmbeddedTools() throws Exception {
	AnalysisMock.get().setupMockToolsRepository(mockToolsConfig);
	}

	@Override
	protected BlazeRuntime.Builder getRuntimeBuilder() throws Exception {
	return super.getRuntimeBuilder()
	.addBlazeModule(new NoSpawnCacheModule())
	.addBlazeModule(new CredentialModule())
	.addBlazeModule(new BazelBuildEventServiceModule());
	}

	private void afterBuildCommand() throws Exception {
	runtimeWrapper.newCommand();
	}

	/**
	* Validates that TargetCompleteEvents do not keep a map of action output metadata for the
	* _validation output group, which can be quite large.
	*/
	@Test
	public void artifactsNotRetained() throws Exception {
	write(
	"validation_actions/defs.bzl",
	"def _rule_with_implicit_outs_and_validation_impl(ctx):",
	"",
	" ctx.actions.write(ctx.outputs.main, \"main output\\n\")",
	"",
	" ctx.actions.write(ctx.outputs.implicit, \"implicit output\\n\")",
	"",
	" validation_output = ctx.actions.declare_file(ctx.attr.name + \".validation\")",
	" # The actual tool will be created in individual tests, depending on whether",
	" # validation should pass or fail.",
	" ctx.actions.run(",
	" outputs = [validation_output],",
	" executable = ctx.executable._validation_tool,",
	" arguments = [validation_output.path])",
	"",
	" return [",
	" DefaultInfo(files = depset([ctx.outputs.main])),",
	" OutputGroupInfo(_validation = depset([validation_output])),",
	" ]",
	"",
	"",
	"rule_with_implicit_outs_and_validation = rule(",
	" implementation = _rule_with_implicit_outs_and_validation_impl,",
	" outputs = {",
	" \"main\": \"%{name}.main\",",
	" \"implicit\": \"%{name}.implicit\",",
	" },",
	" attrs = {",
	" \"_validation_tool\": attr.label(",
	" allow_single_file = True,",
	" default = Label(\"//validation_actions:validation_tool\"),",
	" executable = True,",
	" cfg = \"exec\"),",
	" }",
	")");
	write("validation_actions/validation_tool", "#!/bin/bash", "echo \"validation output\" > $1")
	.setExecutable(true);
	write(
	"validation_actions/BUILD",
	"load(",
	" \":defs.bzl\",",
	" \"rule_with_implicit_outs_and_validation\")",
	"",
	"rule_with_implicit_outs_and_validation(name = \"foo0\")");

	AtomicReference<TargetCompleteEvent> targetCompleteEventRef = new AtomicReference<>();
	runtimeWrapper.registerSubscriber(
	new Object() {
	@SuppressWarnings("unused")
	@Subscribe
	public void accept(TargetCompleteEvent event) {
	targetCompleteEventRef.set(event);
	}
	});

	addOptions("--experimental_run_validations");
	BuildResult buildResult = buildTarget("//validation_actions:foo0");

	Collection<ConfiguredTarget> successfulTargets = buildResult.getSuccessfulTargets();
	ConfiguredTarget fooTarget = Iterables.getOnlyElement(successfulTargets);

	// Check that the primary output, :foo0.main, has its metadata retained.
	Artifact main =
	((RuleConfiguredTarget) fooTarget)
	.findArtifactByOutputLabel(
	Label.parseCanonicalUnchecked("//validation_actions:foo0.main"));
	FileArtifactValue mainMetadata =
	targetCompleteEventRef.get().getCompletionContext().getFileArtifactValue(main);
	assertThat(mainMetadata).isNotNull();

	// Check that the validation output, :foo0.validation, does not have its metadata retained.
	OutputGroupInfo outputGroups = fooTarget.get(OutputGroupInfo.STARLARK_CONSTRUCTOR);
	NestedSet<Artifact> validationArtifacts =
	outputGroups.getOutputGroup(OutputGroupInfo.VALIDATION);
	assertThat(validationArtifacts.isEmpty()).isFalse();

	Artifact validationArtifact = Iterables.getOnlyElement(validationArtifacts.toList());

	FileArtifactValue validationArtifactMetadata =
	targetCompleteEventRef
	.get()
	.getCompletionContext()
	.getFileArtifactValue(validationArtifact);
	assertThat(validationArtifactMetadata).isNull();
	}

	@Test
	public void outputFile() throws Exception {
	write("foo/BUILD", "genrule(name = 'foobin', outs = ['out.txt'], cmd = 'echo -n Hello > $@')");

	File bep = buildTargetAndCaptureBEP("//foo:foobin");

	BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(bep, "out.txt");
	assertThat(outFile).isNotNull();
	assertThat(outFile.getUri()).startsWith("file://");
	assertThat(outFile.getUri()).endsWith("/bin/foo/out.txt");
	assertThat(outFile.getLength()).isEqualTo("Hello".length());
	assertDigest("Hello", BaseEncoding.base16().lowerCase().decode(outFile.getDigest()));
	}

	@Test
	public void outputDirectory() throws Exception {
	write(
	"foo/defs.bzl",
	"def _impl(ctx):",
	" dir = ctx.actions.declare_directory(ctx.label.name)",
	" ctx.actions.run_shell(",
	" outputs = [dir],",
	" command = 'echo -n Hello > %s/file.txt' % dir.path,",
	")",
	" return DefaultInfo(files = depset([dir]))",
	"",
	"directory = rule(implementation = _impl)");
	write("foo/BUILD", "load(':defs.bzl', 'directory')", "directory(name = 'dir')");

	File bep = buildTargetAndCaptureBEP("//foo:dir");

	BuildEventStreamProtos.TargetComplete targetComplete = findTargetCompleteEventInBEPStream(bep);
	assertThat(targetComplete.getDirectoryOutputList()).hasSize(1);
	BuildEventStreamProtos.File dir = targetComplete.getDirectoryOutputList().get(0);
	assertThat(dir.getName()).endsWith("/dir");
	assertThat(dir.getUri()).isEmpty();
	assertThat(dir.getContents()).isEmpty();
	assertThat(dir.getSymlinkTargetPath()).isEmpty();

	BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(bep, "file.txt");
	assertThat(outFile).isNotNull();
	assertThat(outFile.getUri()).startsWith("file://");
	assertThat(outFile.getUri()).endsWith("/bin/foo/dir/file.txt");
	assertThat(outFile.getLength()).isEqualTo("Hello".length());
	assertDigest("Hello", BaseEncoding.base16().lowerCase().decode(outFile.getDigest()));
	}

	@Test
	public void outputSymlink() throws Exception {
	write(
	"foo/defs.bzl",
	"def _impl(ctx):",
	" sym = ctx.actions.declare_symlink(ctx.label.name)",
	" ctx.actions.symlink(output = sym, target_path = '/some/path')",
	" return DefaultInfo(files = depset([sym]))",
	"",
	"symlink = rule(implementation = _impl)");
	write("foo/BUILD", "load(':defs.bzl', 'symlink')", "symlink(name = 'sym')");

	File bep = buildTargetAndCaptureBEP("//foo:sym");

	BuildEventStreamProtos.File outFile = findOutputFileInBEPStream(bep, "sym");
	assertThat(outFile).isNotNull();
	assertThat(outFile.getSymlinkTargetPath()).isEqualTo("/some/path");
	assertThat(outFile.getLength()).isEqualTo(0);
	assertThat(outFile.getDigest()).isEmpty();
	}

	private File buildTargetAndCaptureBEP(String target) throws Exception {
	File bep = tmpFolder.newFile();
	// We use WAIT_FOR_UPLOAD_COMPLETE because it's the easiest way to force the BES module to
	// wait until the BEP binary file has been written.
	addOptions(
	"--build_event_binary_file=" + bep.getAbsolutePath(),
	"--bes_upload_mode=WAIT_FOR_UPLOAD_COMPLETE");
	buildTarget(target);
	// We need to wait for all events to be written to the file, which is done in #afterCommand()
	// if --bes_upload_mode=WAIT_FOR_UPLOAD_COMPLETE.
	afterBuildCommand();
	return bep;
	}

	private static void assertDigest(String contents, byte[] bepDigest) {
	// Try all registered hash functions and verify that one of them was used to produce the digest.
	boolean foundHashFunction = false;
	for (DigestHashFunction hashFunction : DigestHashFunction.getPossibleHashFunctions()) {
	HashCode hashCode = hashFunction.getHashFunction().hashString(contents, UTF_8);
	if (Arrays.equals(bepDigest, hashCode.asBytes())) {
	foundHashFunction = true;
	}
	}
	assertThat(foundHashFunction).isTrue();
	}

	private static ImmutableList<BuildEvent> parseBuildEventsFromBEPStream(File bep)
	throws IOException {
	ImmutableList.Builder<BuildEvent> buildEvents = ImmutableList.builder();
	try (InputStream in = new FileInputStream(bep)) {
	while (in.available() > 0) {
	buildEvents.add(BuildEvent.parseDelimitedFrom(in));
	}
	}
	return buildEvents.build();
	}

	@Nullable
	private static BuildEventStreamProtos.TargetComplete findTargetCompleteEventInBEPStream(File bep)
	throws IOException {
	for (BuildEvent buildEvent : parseBuildEventsFromBEPStream(bep)) {
	if (buildEvent.getId().getIdCase() == IdCase.TARGET_COMPLETED) {
	return buildEvent.getCompleted();
	}
	}
	return null;
	}

	@Nullable
	private static BuildEventStreamProtos.File findOutputFileInBEPStream(File bep, String name)
	throws IOException {
	for (BuildEvent buildEvent : parseBuildEventsFromBEPStream(bep)) {
	if (buildEvent.getId().getIdCase() == IdCase.NAMED_SET) {
	NamedSetOfFiles namedSetOfFiles = buildEvent.getNamedSetOfFiles();
	for (BuildEventStreamProtos.File file : namedSetOfFiles.getFilesList()) {
	if (file.getName().contains(name)) {
	return file;
	}
	}
	}
	}
	return null;
	}
	}