Automated rollback of commit 7e87730de985b7099b9b683571d58efdaab70890.

*** Reason for rollback ***

Go back to the default constructor - instead of requiring everywhere to know the correct hash function, we'll have the default rely on global state. It will make transition easier, even if it makes the origin of the hash less obvious.

*** Original change description ***

Remove default MD5 in most of Bazel's virtual filesystems.

This forces the ex-default to be explicit in a lot of tests, but I'd rather that than have the risk of implicit md5-use in production code.

To keep this CL smaller, do not remove the default from UnixFS quite yet.

RELNOTES: None.
PiperOrigin-RevId: 206358838

63 files changed, 124 insertions, 197 deletions

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 9a06fd4743..fc6376e46f 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
@@ -224,7 +224,7 @@ public class DigestUtilsTest {
     final AtomicInteger getDigestCounter = new AtomicInteger(0);
 
     FileSystem tracingFileSystem =
-        new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5) {
+        new InMemoryFileSystem(BlazeClock.instance()) {
           @Override
           protected byte[] getFastDigest(Path path) throws IOException {
             getFastDigestCounter.incrementAndGet();
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 a658a8146e..5de14d956c 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
@@ -21,7 +21,6 @@ import com.google.devtools.build.lib.actions.util.ActionsTestUtil.UncheckedActio
 import com.google.devtools.build.lib.actions.util.TestAction;
 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;
@@ -37,7 +36,7 @@ import org.junit.runners.JUnit4;
  */
 @RunWith(JUnit4.class)
 public class MapBasedActionGraphTest {
-  private final FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+  private final FileSystem fileSystem = new InMemoryFileSystem();
   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 ec13e93cdb..cd3489ddf5 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
@@ -69,7 +69,6 @@ import com.google.devtools.build.lib.util.FileType;
 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;
@@ -259,8 +258,7 @@ public final class ActionsTestUtil {
   public static final Artifact DUMMY_ARTIFACT =
       new Artifact(
           PathFragment.create("/dummy"),
-          ArtifactRoot.asSourceRoot(
-              Root.absoluteRoot(new InMemoryFileSystem(DigestHashFunction.MD5))));
+          ArtifactRoot.asSourceRoot(Root.absoluteRoot(new InMemoryFileSystem())));
 
   public static final ActionOwner NULL_ACTION_OWNER =
       ActionOwner.create(
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 6273c9816a..67d9b6254a 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
@@ -17,7 +17,6 @@ import static org.junit.Assert.fail;
 
 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.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
@@ -37,7 +36,7 @@ public class AnalysisWithIOExceptionsTest extends AnalysisTestCase {
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5) {
+    return new InMemoryFileSystem(BlazeClock.instance()) {
       @Override
       public FileStatus stat(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 8afbf2d86d..fc1b7078e6 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
@@ -17,7 +17,6 @@ import static org.junit.Assert.fail;
 
 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;
@@ -39,7 +38,7 @@ public class InterruptedExceptionTest extends AnalysisTestCase {
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5) {
+    return new InMemoryFileSystem(BlazeClock.instance()) {
       @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 37b870d9b1..258095fa95 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
@@ -24,7 +24,6 @@ import com.google.devtools.build.lib.actions.ArtifactRoot;
 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;
@@ -197,7 +196,7 @@ final class LocationFunctionBuilder {
   }
 
   private static Artifact makeArtifact(String path) {
-    FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    FileSystem fs = new InMemoryFileSystem();
     if (path.startsWith("/exec/out")) {
       return new Artifact(
           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 d31a5fbc5f..67616fa683 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
@@ -18,7 +18,6 @@ import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.fail;
 
 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;
@@ -32,7 +31,7 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class DecompressorValueTest {
 
-  private FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+  private FileSystem fs = new InMemoryFileSystem();
 
   @Test
   public void testKnownFileExtensionsDoNotThrow() throws Exception {
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 1626cd47b2..ab550a072d 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
@@ -25,7 +25,6 @@ import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.testutil.TestConstants;
-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;
@@ -57,7 +56,7 @@ public class SymlinkForestTest {
   @Before
   public final void initializeFileSystem() throws Exception {
     ManualClock clock = new ManualClock();
-    fileSystem = new InMemoryFileSystem(clock, DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem(clock);
     linkRoot = fileSystem.getPath("/linkRoot");
     createDirectoryAndParents(linkRoot);
   }
diff --git a/src/test/java/com/google/devtools/build/lib/exec/AbstractSpawnStrategyTest.java b/src/test/java/com/google/devtools/build/lib/exec/AbstractSpawnStrategyTest.java
index 1ea3935748..d92a1b155e 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/AbstractSpawnStrategyTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/AbstractSpawnStrategyTest.java
@@ -40,7 +40,6 @@ import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.testutil.Suite;
 import com.google.devtools.build.lib.testutil.TestSpec;
 import com.google.devtools.build.lib.util.io.MessageOutputStream;
-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;
@@ -66,7 +65,7 @@ public class AbstractSpawnStrategyTest {
   private static final Spawn SIMPLE_SPAWN =
       new SpawnBuilder("/bin/echo", "Hi!").withEnvironment("VARIABLE", "value").build();
 
-  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+  private final FileSystem fs = new InMemoryFileSystem();
   private final Path execRoot = fs.getPath("/execroot");
   private Scratch scratch;
   private ArtifactRoot rootDir;
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 0390a01a80..1dcd3b0e11 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
@@ -27,7 +27,6 @@ import com.google.devtools.build.lib.events.StoredEventHandler;
 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;
@@ -48,7 +47,7 @@ public class BlazeExecutorTest {
 
   @Before
   public final void setUpDirectoriesAndTools() throws Exception {
-    fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem();
     directories =
         new BlazeDirectories(
             new ServerDirectories(
diff --git a/src/test/java/com/google/devtools/build/lib/exec/FilesetManifestTest.java b/src/test/java/com/google/devtools/build/lib/exec/FilesetManifestTest.java
index 7906788e53..2db666eb19 100644
--- a/src/test/java/com/google/devtools/build/lib/exec/FilesetManifestTest.java
+++ b/src/test/java/com/google/devtools/build/lib/exec/FilesetManifestTest.java
@@ -21,7 +21,6 @@ import static org.junit.Assert.fail;
 
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.ArtifactRoot;
-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;
@@ -45,7 +44,7 @@ public class FilesetManifestTest {
 
   @Before
   public final void createSpawnInputExpander() throws Exception  {
-    fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem();
     execRoot = fs.getPath("/root");
   }
 
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 4b054a795e..c3fa2dbc4b 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
@@ -57,7 +57,7 @@ public class SingleBuildFileCacheTest {
     calls = new HashMap<>();
     md5Overrides = new HashMap<>();
     fs =
-        new InMemoryFileSystem(DigestHashFunction.MD5) {
+        new InMemoryFileSystem() {
           @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 f8b59a07f5..e21fdbb4e8 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
@@ -33,7 +33,6 @@ import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.analysis.Runfiles;
 import com.google.devtools.build.lib.analysis.RunfilesSupplierImpl;
 import com.google.devtools.build.lib.exec.util.FakeActionInputFileCache;
-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 +62,7 @@ public class SpawnInputExpanderTest {
 
   @Before
   public final void createSpawnInputExpander() throws Exception  {
-    fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem();
     execRoot = fs.getPath("/root");
     expander = new SpawnInputExpander(execRoot, /*strict=*/ true);
     inputMappings = Maps.newHashMap();
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 2e25907160..808fe36027 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
@@ -24,7 +24,6 @@ import com.google.devtools.build.lib.actions.ActionInputHelper;
 import com.google.devtools.build.lib.actions.ExecutionRequirements;
 import com.google.devtools.build.lib.actions.Spawn;
 import com.google.devtools.build.lib.exec.util.FakeOwner;
-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;
@@ -35,7 +34,7 @@ import org.junit.runners.JUnit4;
 /** Unit tests for {@link SymlinkTreeHelper}. */
 @RunWith(JUnit4.class)
 public final class SymlinkTreeHelperTest {
-  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+  private final FileSystem fs = new InMemoryFileSystem();
 
   @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 e4fc2bcc69..35f7365afa 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
@@ -54,7 +54,6 @@ import com.google.devtools.build.lib.unix.UnixFileSystem;
 import com.google.devtools.build.lib.util.NetUtil;
 import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.build.lib.util.io.FileOutErr;
-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;
@@ -274,7 +273,7 @@ public class LocalSpawnRunnerTest {
     SubprocessBuilder.setSubprocessFactory(new SubprocessInterceptor());
     resourceManager.setAvailableResources(
         ResourceSet.create(/*memoryMb=*/1, /*cpuUsage=*/1, /*ioUsage=*/1, /*localTestCount=*/1));
-    return new InMemoryFileSystem(DigestHashFunction.MD5);
+    return new InMemoryFileSystem();
   }
 
   /**
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 7b9de78167..eb614fc49c 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
@@ -36,7 +36,6 @@ import com.google.devtools.build.lib.syntax.Printer;
 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;
@@ -121,7 +120,7 @@ public abstract class PackageFactoryTestBase {
   @Before
   public final void initializeFileSystem() throws Exception {
     FileSystem fs =
-        new InMemoryFileSystem(DigestHashFunction.MD5) {
+        new InMemoryFileSystem() {
           @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 3b57806ab6..2890619c2e 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
@@ -37,7 +37,6 @@ import com.google.devtools.build.lib.testutil.FoundationTestCase;
 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.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
@@ -135,7 +134,7 @@ public class BuildFileModificationTest extends FoundationTestCase {
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(clock, DigestHashFunction.MD5);
+    return new InMemoryFileSystem(clock);
   }
 
   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 fdd96234ed..de8e71b221 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
@@ -24,7 +24,6 @@ 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;
@@ -83,8 +82,7 @@ public class IOExceptionsTest extends PackageLoadingTestCase {
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(
-        BlazeClock.instance(), PathFragment.create(FS_ROOT), DigestHashFunction.MD5) {
+    return new InMemoryFileSystem(BlazeClock.instance(), PathFragment.create(FS_ROOT)) {
       @Override
       public FileStatus stat(Path path, boolean followSymlinks) throws IOException {
         String crash = crashMessage.apply(path);
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 e6cb8562b1..866844df31 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
@@ -46,7 +46,6 @@ import com.google.devtools.build.lib.skyframe.SkyframeExecutor;
 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.FileSystem;
@@ -87,7 +86,7 @@ public class IncrementalLoadingTest {
   public final void createTester() throws Exception {
     ManualClock clock = new ManualClock();
     FileSystem fs =
-        new InMemoryFileSystem(clock, DigestHashFunction.MD5) {
+        new InMemoryFileSystem(clock) {
           @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 d2039af36f..50e6ecf0e6 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
@@ -55,7 +55,6 @@ import com.google.devtools.build.lib.testutil.ManualClock;
 import com.google.devtools.build.lib.testutil.MoreAsserts;
 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.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
@@ -716,7 +715,7 @@ public class LoadingPhaseRunnerTest {
     private MockToolsConfig mockToolsConfig;
 
     public LoadingPhaseTester() throws IOException {
-      FileSystem fs = new InMemoryFileSystem(clock, DigestHashFunction.MD5);
+      FileSystem fs = new InMemoryFileSystem(clock);
       this.workspace = fs.getPath("/workspace");
       workspace.createDirectory();
       mockToolsConfig = new MockToolsConfig(workspace);
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 1f0bb9d86a..f2a7233b69 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
@@ -17,7 +17,6 @@ import com.google.common.collect.ImmutableSet;
 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;
@@ -58,8 +57,7 @@ public class TargetPatternEvaluatorIOTest extends AbstractTargetPatternEvaluator
 
   @Override
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(
-        BlazeClock.instance(), PathFragment.create(FS_ROOT), DigestHashFunction.MD5) {
+    return new InMemoryFileSystem(BlazeClock.instance(), PathFragment.create(FS_ROOT)) {
       @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 1022f38d92..044ae8c0d4 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
@@ -17,7 +17,6 @@ import com.google.caliper.BeforeExperiment;
 import com.google.caliper.Benchmark;
 import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.profiler.Profiler.ProfiledTaskKinds;
-import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 
 /**
@@ -28,15 +27,14 @@ public class AutoProfilerBenchmark {
 
   @BeforeExperiment
   void startProfiler() throws Exception {
-    Profiler.instance()
-        .start(
-            ProfiledTaskKinds.ALL,
-            new InMemoryFileSystem(DigestHashFunction.MD5).getPath("/out.dat").getOutputStream(),
-            Profiler.Format.BINARY_BAZEL_FORMAT,
-            "benchmark",
-            false,
-            BlazeClock.instance(),
-            BlazeClock.instance().nanoTime());
+    Profiler.instance().start(
+        ProfiledTaskKinds.ALL,
+        new InMemoryFileSystem().getPath("/out.dat").getOutputStream(),
+        Profiler.Format.BINARY_BAZEL_FORMAT,
+        "benchmark",
+        false,
+        BlazeClock.instance(),
+        BlazeClock.instance().nanoTime());
   }
 
   @BeforeExperiment
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 2eabbba2d3..dad6ee04fe 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
@@ -36,7 +36,6 @@ import com.google.devtools.build.lib.events.StoredEventHandler;
 import com.google.devtools.build.lib.packages.AbstractRuleErrorConsumer;
 import com.google.devtools.build.lib.packages.RuleErrorConsumer;
 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;
@@ -185,7 +184,7 @@ public abstract class ResourceTestBase extends AndroidBuildViewTestCase {
   @Before
   public void setup() {
     errorConsumer = new FakeRuleErrorConsumer();
-    fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem();
     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 105b8f7b82..831cf95350 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
@@ -26,7 +26,6 @@ import com.google.devtools.build.lib.actions.ArtifactResolver;
 import com.google.devtools.build.lib.actions.ArtifactRoot;
 import com.google.devtools.build.lib.actions.util.ActionsTestUtil;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
-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 +37,7 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class HeaderDiscoveryTest {
 
-  private final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+  private final FileSystem fs = new InMemoryFileSystem();
   private final Path execRoot = fs.getPath("/execroot");
   private final Path derivedRoot = execRoot.getRelative("derived");
   private final ArtifactRoot artifactRoot = ArtifactRoot.asDerivedRoot(execRoot, derivedRoot);
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 72424d092f..2a55081e99 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
@@ -18,7 +18,6 @@ import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.devtools.build.lib.util.io.FileOutErr;
-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;
@@ -44,7 +43,7 @@ public class ShowIncludesFilterTest {
     showIncludesFilter = new ShowIncludesFilter("foo.cpp");
     output = new ByteArrayOutputStream();
     filterOutputStream = showIncludesFilter.getFilteredOutputStream(output);
-    fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem();
     fs.getPath("/out").createDirectory();
   }
 
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 5edf6807ff..1e2311fa84 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
@@ -34,7 +34,6 @@ import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.rules.proto.ProtoCompileActionBuilder.ToolchainInvocation;
 import com.google.devtools.build.lib.util.LazyString;
-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;
@@ -46,8 +45,7 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class ProtoCompileActionBuilderTest {
 
-  private static final InMemoryFileSystem FILE_SYSTEM =
-      new InMemoryFileSystem(DigestHashFunction.MD5);
+  private static final InMemoryFileSystem FILE_SYSTEM = new InMemoryFileSystem();
   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/ProcessWrapperUtilTest.java b/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperUtilTest.java
index adefde3b0c..ff1fdd50d5 100644
--- a/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperUtilTest.java
+++ b/src/test/java/com/google/devtools/build/lib/runtime/ProcessWrapperUtilTest.java
@@ -17,7 +17,6 @@ package com.google.devtools.build.lib.runtime;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.common.collect.ImmutableList;
-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;
@@ -35,7 +34,7 @@ public final class ProcessWrapperUtilTest {
 
   @Before
   public final void createFileSystem() {
-    testFS = new InMemoryFileSystem(DigestHashFunction.MD5);
+    testFS = new InMemoryFileSystem();
   }
 
   @Test
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 a033517d35..ee0f08c041 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
@@ -29,7 +29,6 @@ import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 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;
@@ -64,7 +63,7 @@ public class TestSummaryTest {
 
   @Before
   public final void createFileSystem() throws Exception  {
-    fs = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem(BlazeClock.instance());
     stubTarget = stubTarget();
     basicBuilder = getTemplateBuilder();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessTest.java b/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessTest.java
index 994ae2c70e..06c6b2b234 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessTest.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/FakeSandboxfsProcessTest.java
@@ -17,7 +17,6 @@ package com.google.devtools.build.lib.sandbox;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.devtools.build.lib.testutil.MoreAsserts.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;
@@ -33,7 +32,7 @@ public class FakeSandboxfsProcessTest extends BaseSandboxfsProcessTest {
 
   @Override
   Path newTmpDir() throws IOException {
-    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    FileSystem fileSystem = new InMemoryFileSystem();
     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 6ba265103e..8a2b4b3a75 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
@@ -20,7 +20,6 @@ import static com.google.devtools.build.lib.testutil.MoreAsserts.assertThrows;
 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;
@@ -38,7 +37,7 @@ public final class LinuxSandboxUtilTest {
 
   @Before
   public final void createFileSystem() {
-    testFS = new InMemoryFileSystem(DigestHashFunction.MD5);
+    testFS = new InMemoryFileSystem();
   }
 
   @Test
@@ -98,7 +97,7 @@ public final class LinuxSandboxUtilTest {
     boolean useFakeHostname = true;
     boolean useDebugMode = true;
 
-    FileSystem fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    FileSystem fileSystem = new InMemoryFileSystem();
     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/SandboxTestCase.java b/src/test/java/com/google/devtools/build/lib/sandbox/SandboxTestCase.java
index 0b26414f95..8489c7d914 100644
--- a/src/test/java/com/google/devtools/build/lib/sandbox/SandboxTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/sandbox/SandboxTestCase.java
@@ -14,7 +14,6 @@
 package com.google.devtools.build.lib.sandbox;
 
 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.Path;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
@@ -27,7 +26,7 @@ public class SandboxTestCase {
 
   @Before
   public final void createTestRoot() throws Exception {
-    fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem();
     testRoot = fileSystem.getPath(TestUtils.tmpDir());
     testRoot.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 123da88426..5395b90a8c 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
@@ -23,7 +23,6 @@ import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.packages.NoSuchPackageException;
 import com.google.devtools.build.lib.skyframe.util.SkyframeExecutorTestUtils;
 import com.google.devtools.build.lib.syntax.SkylarkImport;
-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;
@@ -45,10 +44,6 @@ public class ASTFileLookupFunctionTest extends BuildViewTestCase {
   private class MockFileSystem extends InMemoryFileSystem {
     boolean statThrowsIoException;
 
-    private MockFileSystem() {
-      super(DigestHashFunction.MD5);
-    }
-
     @Override
     public FileStatus stat(Path path, boolean followSymlinks) throws IOException {
       if (statThrowsIoException
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 e8e0e0bcfb..5a1ca443b1 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
@@ -31,7 +31,6 @@ import com.google.devtools.build.lib.testutil.TestConstants;
 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;
@@ -162,11 +161,6 @@ abstract class ArtifactFunctionTestCase {
 
   /** InMemoryFileSystem that can pretend to do a fast digest. */
   protected class CustomInMemoryFs extends InMemoryFileSystem {
-
-    CustomInMemoryFs() {
-      super(DigestHashFunction.MD5);
-    }
-
     @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/DiffAwarenessManagerTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/DiffAwarenessManagerTest.java
index 6b5d6250ec..5dbbaba462 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
@@ -21,7 +21,6 @@ import com.google.common.collect.ImmutableList;
 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;
@@ -47,7 +46,7 @@ public class DiffAwarenessManagerTest {
 
   @Before
   public final void createFileSystem() throws Exception  {
-    fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem();
   }
 
   @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 e437987201..1e85b6c8b3 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
@@ -21,7 +21,6 @@ import com.google.common.io.BaseEncoding;
 import com.google.common.testing.EqualsTester;
 import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.testutil.ManualClock;
-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;
@@ -34,7 +33,7 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class FileArtifactValueTest {
   private final ManualClock clock = new ManualClock();
-  private final FileSystem fs = new InMemoryFileSystem(clock, DigestHashFunction.MD5);
+  private final FileSystem fs = new InMemoryFileSystem(clock);
 
   private Path scratchFile(String name, long mtime, String content) throws IOException {
     Path path = fs.getPath(name);
@@ -160,7 +159,7 @@ public class FileArtifactValueTest {
   public void testIOException() throws Exception {
     final IOException exception = new IOException("beep");
     FileSystem fs =
-        new InMemoryFileSystem(DigestHashFunction.MD5) {
+        new InMemoryFileSystem() {
           @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 4d3a7d5228..b76bbcd24d 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
@@ -52,7 +52,6 @@ import com.google.devtools.build.lib.testutil.TestRuleClassProvider;
 import com.google.devtools.build.lib.testutil.TestUtils;
 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.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -1613,7 +1612,7 @@ public class FileFunctionTest {
     private final Map<Path, IOException> stubbedFastDigestErrors = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock, DigestHashFunction.MD5);
+      super(manualClock);
     }
 
     public 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 a092445829..38bffd74c5 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
@@ -15,7 +15,6 @@ package com.google.devtools.build.lib.skyframe;
 
 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;
@@ -29,7 +28,7 @@ public class FileSymlinkCycleUniquenessFunctionTest {
 
   @Test
   public void testHashCodeAndEqualsContract() throws Exception {
-    Root root = Root.fromPath(new InMemoryFileSystem(DigestHashFunction.MD5).getPath("/root"));
+    Root root = Root.fromPath(new InMemoryFileSystem().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/FilesystemValueCheckerTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java
index 6ab8e17f37..8ae221911e 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/FilesystemValueCheckerTest.java
@@ -48,7 +48,6 @@ import com.google.devtools.build.lib.testutil.TimestampGranularityUtils;
 import com.google.devtools.build.lib.util.io.OutErr;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
 import com.google.devtools.build.lib.vfs.BatchStat;
-import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileStatusWithDigest;
 import com.google.devtools.build.lib.vfs.FileStatusWithDigestAdapter;
@@ -840,7 +839,7 @@ public class FilesystemValueCheckerTest {
     boolean readlinkThrowsIoException;
 
     MockFileSystem() {
-      super(DigestHashFunction.MD5);
+      super();
     }
 
     @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 39ca9f97fb..7d118c6f0c 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
@@ -43,7 +43,6 @@ import com.google.devtools.build.lib.syntax.SkylarkSemantics;
 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;
@@ -782,7 +781,7 @@ public abstract class GlobFunctionTest {
     private Map<Path, FileStatus> stubbedStats = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock, DigestHashFunction.MD5);
+      super(manualClock);
     }
 
     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 da6a1d4a27..0dd046d67d 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
@@ -36,7 +36,6 @@ import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
 import com.google.devtools.build.lib.skyframe.util.SkyframeExecutorTestUtils;
 import com.google.devtools.build.lib.testutil.ManualClock;
 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;
@@ -761,7 +760,7 @@ public class PackageFunctionTest extends BuildViewTestCase {
     private final Map<Path, IOException> pathsToErrorOnGetInputStream = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock, DigestHashFunction.MD5);
+      super(manualClock);
     }
 
     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 9065ef17ab..b03a0e9eae 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
@@ -41,7 +41,6 @@ import com.google.devtools.build.lib.testutil.BlazeTestUtils;
 import com.google.devtools.build.lib.testutil.Suite;
 import com.google.devtools.build.lib.testutil.TestSpec;
 import com.google.devtools.build.lib.testutil.TestUtils;
-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;
@@ -239,59 +238,58 @@ public class ParallelBuilderTest extends TimestampBuilderTestCase {
 
   @Test
   public void testUpdateCacheError() throws Exception {
-    FileSystem fs =
-        new InMemoryFileSystem(DigestHashFunction.MD5) {
-          @Override
-          public FileStatus stat(Path path, boolean followSymlinks) throws IOException {
-            final FileStatus stat = super.stat(path, followSymlinks);
-            if (path.toString().endsWith("/out/foo")) {
-              return new FileStatus() {
-                private final FileStatus original = stat;
+    FileSystem fs = new InMemoryFileSystem() {
+      @Override
+      public FileStatus stat(Path path, boolean followSymlinks) throws IOException {
+        final FileStatus stat = super.stat(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, emptySet, ImmutableList.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 1a380f5f4b..fae9d22012 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
@@ -35,7 +35,6 @@ import com.google.devtools.build.lib.packages.Target;
 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;
@@ -247,7 +246,7 @@ abstract public class SkyframeLabelVisitorTestCase extends PackageLoadingTestCas
     private Map<Path, FileStatus> stubbedStats = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock, DigestHashFunction.MD5);
+      super(manualClock);
     }
 
     public void stubStat(Path path, @Nullable FileStatus stubbedResult) {
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/TargetMarkerFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/TargetMarkerFunctionTest.java
index fb43ad26e1..6778dc8862 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/TargetMarkerFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/TargetMarkerFunctionTest.java
@@ -25,7 +25,6 @@ import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.packages.BuildFileNotFoundException;
 import com.google.devtools.build.lib.packages.NoSuchTargetException;
 import com.google.devtools.build.lib.skyframe.util.SkyframeExecutorTestUtils;
-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;
@@ -146,7 +145,7 @@ public class TargetMarkerFunctionTest extends BuildViewTestCase {
     private Map<Path, IOException> stubbedStatExceptions = Maps.newHashMap();
 
     public CustomInMemoryFs() {
-      super(BlazeClock.instance(), DigestHashFunction.MD5);
+      super(BlazeClock.instance());
     }
 
     public void stubStatIOException(Path path, IOException stubbedResult) {
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 1da13d530b..d83b570366 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
@@ -27,7 +27,6 @@ import com.google.devtools.build.lib.events.Reporter;
 import com.google.devtools.build.lib.events.StoredEventHandler;
 import com.google.devtools.build.lib.packages.NoSuchPackageException;
 import com.google.devtools.build.lib.packages.Package;
-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;
@@ -45,7 +44,7 @@ public abstract class AbstractPackageLoaderTest {
 
   @Before
   public final void init() throws Exception {
-    fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem();
     workspaceDir = fs.getPath("/workspace/");
     workspaceDir.createDirectoryAndParents();
     reporter = new Reporter(new EventBus());
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 0641e65b10..f93d93612b 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
@@ -22,7 +22,6 @@ import com.google.devtools.build.lib.events.EventCollector;
 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.inmemoryfs.InMemoryFileSystem;
@@ -96,7 +95,7 @@ public abstract class FoundationTestCase {
    * Creates the file system; override to inject FS behavior.
    */
   protected FileSystem createFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    return new InMemoryFileSystem(BlazeClock.instance());
   }
 
   // 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 34538f78dd..e5bf9ea8e9 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
@@ -16,7 +16,6 @@ package com.google.devtools.build.lib.testutil;
 
 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;
@@ -42,14 +41,14 @@ public final class Scratch {
    * Create a new ScratchFileSystem using the {@link InMemoryFileSystem}
    */
   public Scratch() {
-    this(new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5), "/");
+    this(new InMemoryFileSystem(BlazeClock.instance()), "/");
   }
 
   /**
    * Create a new ScratchFileSystem using the {@link InMemoryFileSystem}
    */
   public Scratch(String workingDir) {
-    this(new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5), workingDir);
+    this(new InMemoryFileSystem(BlazeClock.instance()), 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 1aec571db5..fb912c5320 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
@@ -14,7 +14,6 @@
 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;
@@ -39,7 +38,7 @@ public class TestFileOutErr extends FileOutErr {
   }
 
   private static Path newInMemoryFile(File root, String name) {
-    InMemoryFileSystem inMemFS = new InMemoryFileSystem(DigestHashFunction.MD5);
+    InMemoryFileSystem inMemFS = new InMemoryFileSystem();
     Path directory = inMemFS.getPath(root.getPath());
     try {
       FileSystemUtils.createDirectoryAndParents(directory);
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 fa6faf8353..9662ca5fa6 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
@@ -19,7 +19,6 @@ import com.google.common.base.Joiner;
 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;
@@ -84,7 +83,7 @@ public class FileTypeTest {
 
   @Test
   public void handlesPathObjects() {
-    Path readme = new InMemoryFileSystem(DigestHashFunction.MD5).getPath("/readme.txt");
+    Path readme = new InMemoryFileSystem().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 c5dd670344..372b48d80c 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
@@ -18,7 +18,6 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 
 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;
@@ -117,7 +116,7 @@ public class FingerprintTest {
     PathFragment pf = PathFragment.create("/etc/pwd");
     assertThat(new Fingerprint().addPath(pf).hexDigestAndReset())
         .isEqualTo("63ab5c47c117635407a1af6377e216bc");
-    Path p = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5).getPath(pf);
+    Path p = new InMemoryFileSystem(BlazeClock.instance()).getPath(pf);
     assertThat(new Fingerprint().addPath(p).hexDigestAndReset())
         .isEqualTo("63ab5c47c117635407a1af6377e216bc");
   }
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 b55d47542a..cd6be682a2 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
@@ -56,7 +56,7 @@ public class FileSystemUtilsTest {
   @Before
   public final void initializeFileSystem() throws Exception  {
     clock = new ManualClock();
-    fileSystem = new InMemoryFileSystem(clock, DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem(clock);
     workingDir = fileSystem.getPath("/workingDir");
     workingDir.createDirectory();
   }
@@ -372,11 +372,6 @@ public class FileSystemUtilsTest {
   @Test
   public void testMoveFileAcrossDevices() throws Exception {
     class MultipleDeviceFS extends InMemoryFileSystem {
-
-      MultipleDeviceFS() {
-        super(DigestHashFunction.MD5);
-      }
-
       @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 0a080f4792..5b0958fae1 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
@@ -54,16 +54,15 @@ public class GlobTest {
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    fs =
-        new InMemoryFileSystem(DigestHashFunction.MD5) {
-          @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() {
+      @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);
+      }
+    };
     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/JavaIoFileSystemTest.java b/src/test/java/com/google/devtools/build/lib/vfs/JavaIoFileSystemTest.java
index ccafd494a9..056b5f0f1a 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/JavaIoFileSystemTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/JavaIoFileSystemTest.java
@@ -50,7 +50,7 @@ public class JavaIoFileSystemTest extends SymlinkAwareFileSystemTest {
   @Override
   public FileSystem getFreshFileSystem() {
     clock = new ManualClock();
-    return new JavaIoFileSystem(clock, DigestHashFunction.MD5);
+    return new JavaIoFileSystem(clock);
   }
 
   // Tests are inherited from the FileSystemTest
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 4fa70628bd..7494683391 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 @@ public abstract class PathAbstractTest {
 
   @Before
   public void setup() {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
     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 20deec04c3..78986e0f5e 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
@@ -40,7 +40,7 @@ public class PathFragmentTest {
 
   @Test
   public void testEqualsAndHashCode() {
-    InMemoryFileSystem filesystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    InMemoryFileSystem filesystem = new InMemoryFileSystem();
 
     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 d57f23f1b0..51b3e79529 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 @@ public class RecursiveGlobTest {
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
     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 5d15bf9ed2..640f8c4c91 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
@@ -35,12 +35,12 @@ public class RootTest {
 
   @Before
   public final void initializeFileSystem() throws Exception {
-    fs = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    fs = new InMemoryFileSystem(BlazeClock.instance());
   }
 
   @Test
   public void testEqualsAndHashCodeContract() throws Exception {
-    FileSystem otherFs = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    FileSystem otherFs = new InMemoryFileSystem(BlazeClock.instance());
     new EqualsTester()
         .addEqualityGroup(Root.absoluteRoot(fs), Root.absoluteRoot(fs))
         .addEqualityGroup(Root.absoluteRoot(otherFs), Root.absoluteRoot(otherFs))
@@ -68,7 +68,7 @@ public class RootTest {
 
   @Test
   public void testFilesystemTransform() throws Exception {
-    FileSystem fs2 = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    FileSystem fs2 = new InMemoryFileSystem(BlazeClock.instance());
     Root root = Root.fromPath(fs.getPath("/foo"));
     Root root2 = Root.toFileSystem(root, fs2);
     assertThat(root2.asPath().getFileSystem()).isSameAs(fs2);
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 aa1513f734..6f452c2fcb 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
@@ -31,7 +31,7 @@ public class RootedPathTest {
 
   @Before
   public final void initializeFileSystem() throws Exception  {
-    filesystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    filesystem = new InMemoryFileSystem(BlazeClock.instance());
     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 01069d1e8e..e815a8cc23 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 @@ import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
 public class SearchPathTest {
-  private FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+  private FileSystem fs = new InMemoryFileSystem();
 
   @Test
   public void testNull() throws Exception {
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystemTest.java b/src/test/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystemTest.java
index 8c1ffac7c2..6f2b4e7858 100644
--- a/src/test/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystemTest.java
+++ b/src/test/java/com/google/devtools/build/lib/vfs/inmemoryfs/InMemoryFileSystemTest.java
@@ -19,7 +19,6 @@ import static org.junit.Assert.fail;
 import com.google.common.collect.Lists;
 import com.google.devtools.build.lib.clock.BlazeClock;
 import com.google.devtools.build.lib.testutil.TestThread;
-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;
@@ -45,7 +44,7 @@ public class InMemoryFileSystemTest extends SymlinkAwareFileSystemTest {
 
   @Override
   public FileSystem getFreshFileSystem() {
-    return new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    return new InMemoryFileSystem(BlazeClock.instance());
   }
 
   @Override
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 1305c992b6..1f78b189bf 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
@@ -16,7 +16,6 @@ package com.google.devtools.build.lib.vfs.util;
 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;
@@ -69,7 +68,7 @@ public class FsApparatus {
   }
 
   private FsApparatus() {
-    fileSystem = new InMemoryFileSystem(BlazeClock.instance(), DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem(BlazeClock.instance());
     workingDir = fileSystem.getPath("/");
   }
 
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 98de2b8186..4607b22e74 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
@@ -18,7 +18,6 @@ import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.devtools.build.lib.util.OS;
-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;
@@ -86,7 +85,7 @@ public class ErrorMessageTest {
 
   @Test
   public void testErrorMessageWithLogFile() throws Exception {
-    InMemoryFileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    InMemoryFileSystem fs = new InMemoryFileSystem();
     Path logFile = fs.getPath("/log.txt");
     FileSystemUtils.writeContent(logFile, UTF_8, logText);
     ErrorMessage errorMessage =
@@ -105,7 +104,7 @@ public class ErrorMessageTest {
       // TODO(#3536): This test is failing on Windows, probably due to line breaks. Fix it!
       return;
     }
-    InMemoryFileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+    InMemoryFileSystem fs = new InMemoryFileSystem();
     // 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 2eb8981feb..b7758e66a5 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
@@ -18,7 +18,6 @@ import static com.google.common.truth.Truth.assertThat;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 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;
@@ -42,7 +41,7 @@ public class WorkerExecRootTest {
 
   @Before
   public final void setupTestDirs() throws IOException {
-    fileSystem = new InMemoryFileSystem(DigestHashFunction.MD5);
+    fileSystem = new InMemoryFileSystem();
     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 36f569f138..0552cb8c5a 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
@@ -19,7 +19,6 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.hash.HashCode;
-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 +30,7 @@ import org.junit.runners.JUnit4;
 @RunWith(JUnit4.class)
 public class WorkerFactoryTest {
 
-  final FileSystem fs = new InMemoryFileSystem(DigestHashFunction.MD5);
+  final FileSystem fs = new InMemoryFileSystem();
 
   /**
    * Regression test for b/64689608: The execroot of the sandboxed worker process must end with the