Assign unique work directory for worker for each test case

Closes #17542.

PiperOrigin-RevId: 511166369
Change-Id: I9f747b8081dbae6d5df25e22a47f3d0a3b777af5

src/test/java/com/google/devtools/build/lib/remote/util/IntegrationTestUtils.java

diff --git a/src/test/java/com/google/devtools/build/lib/remote/util/IntegrationTestUtils.java b/src/test/java/com/google/devtools/build/lib/remote/util/IntegrationTestUtils.java
index ded66dd..5c05143 100644
--- a/src/test/java/com/google/devtools/build/lib/remote/util/IntegrationTestUtils.java
+++ b/src/test/java/com/google/devtools/build/lib/remote/util/IntegrationTestUtils.java
@@ -35,6 +35,7 @@
 import java.nio.file.Paths;
 import java.util.Comparator;
 import java.util.Random;
+import java.util.concurrent.atomic.AtomicInteger;
 import javax.annotation.Nullable;
 
 /** Integration test utilities. */
@@ -46,6 +47,8 @@
           "io_bazel/src/tools/remote/worker"
               + (OS.getCurrent() == OS.WINDOWS ? ".exe" : ""));
 
+  private static final AtomicInteger WORKER_COUNTER = new AtomicInteger(0);
+
   private static boolean isPortAvailable(int port) {
     if (port < 1024 || port > 65535) {
       return false;
@@ -115,7 +118,7 @@
     PathFragment workPath = testTmpDir.getRelative("remote.work_path");
     PathFragment casPath = testTmpDir.getRelative("remote.cas_path");
     int workerPort = pickUnusedRandomPort();
-    var worker = new WorkerInstance(useHttp, workerPort, workPath, casPath);
+    var worker = new WorkerInstance(WORKER_COUNTER, useHttp, workerPort, workPath, casPath);
     worker.start();
     return worker;
   }
@@ -125,27 +128,44 @@
     if (dir.exists()) {
       throw new IOException(path + " already exists");
     }
-    if (!dir.mkdir()) {
+    if (!dir.mkdirs()) {
       throw new IOException("Failed to create directory " + path);
     }
   }
 
   public static class WorkerInstance {
-    @Nullable private Subprocess process;
+    private final AtomicInteger counter;
     private final boolean useHttp;
     private final int port;
-    private final PathFragment workPath;
-    private final PathFragment casPath;
+    private final PathFragment workPathPrefix;
+    private final PathFragment casPathPrefix;
 
-    private WorkerInstance(boolean useHttp, int port, PathFragment workPath, PathFragment casPath) {
+    @Nullable private Subprocess process;
+    @Nullable PathFragment workPath;
+    @Nullable PathFragment casPath;
+
+    private WorkerInstance(
+        AtomicInteger counter,
+        boolean useHttp,
+        int port,
+        PathFragment workPathPrefix,
+        PathFragment casPathPrefix) {
+      this.counter = counter;
       this.useHttp = useHttp;
       this.port = port;
-      this.workPath = workPath;
-      this.casPath = casPath;
+      this.workPathPrefix = workPathPrefix;
+      this.casPathPrefix = casPathPrefix;
     }
 
     private void start() throws IOException, InterruptedException {
       Preconditions.checkState(process == null);
+      Preconditions.checkState(workPath == null);
+      Preconditions.checkState(casPath == null);
+
+      var suffix = String.valueOf(counter.getAndIncrement());
+      workPath = workPathPrefix.getRelative(suffix);
+      casPath = casPathPrefix.getRelative(suffix);
+
       ensureMkdir(workPath);
       ensureMkdir(casPath);
       String workerPath = Runfiles.create().rlocation(WORKER_PATH.getSafePathString());
@@ -167,7 +187,10 @@
       process = null;
 
       deleteDir(workPath);
+      workPath = null;
+
       deleteDir(casPath);
+      casPath = null;
     }
 
     public void restart() throws IOException, InterruptedException {
@@ -184,13 +207,5 @@
     public int getPort() {
       return port;
     }
-
-    public PathFragment getWorkPath() {
-      return workPath;
-    }
-
-    public PathFragment getCasPath() {
-      return casPath;
-    }
   }
 }