1 files changed, 61 insertions, 0 deletions
diff --git a/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionsTest.java
new file mode 100644
index 0000000000..6b3b19923d
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/vfs/DigestHashFunctionsTest.java
@@ -0,0 +1,61 @@
+// Copyright 2018 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.vfs;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import java.nio.charset.StandardCharsets;
+import java.util.Collection;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+/**
+ * Tests different {@link DigestHashFunction} for consistency between the MessageDigests and the
+ * HashFunctions that it exposes.
+ */
+@RunWith(Parameterized.class)
+public class DigestHashFunctionsTest {
+  @Parameters(name = "{index}: digestHashFunction={0}")
+  public static Collection<DigestHashFunction[]> hashFunctions() {
+    // TODO(b/112537387): Remove the array-ification and return Collection<DigestHashFunction>. This
+    // is possible in Junit4.12, but 4.11 requires the array. Bazel 0.18 will have Junit4.12, so
+    // this can change then.
+    return DigestHashFunction.getPossibleHashFunctions()
+        .stream()
+        .map(dhf -> new DigestHashFunction[] {dhf})
+        .collect(ImmutableList.toImmutableList());
+  }
+
+  @Parameter public DigestHashFunction digestHashFunction;
+
+  private void assertHashFunctionAndMessageDigestEquivalentForInput(byte[] input) {
+    byte[] hashFunctionOutput = digestHashFunction.getHashFunction().hashBytes(input).asBytes();
+    byte[] messageDigestOutput = digestHashFunction.cloneOrCreateMessageDigest().digest(input);
+    assertThat(hashFunctionOutput).isEqualTo(messageDigestOutput);
+  }
+
+  @Test
+  public void emptyDigestIsConsistent() {
+    assertHashFunctionAndMessageDigestEquivalentForInput(new byte[] {});
+  }
+
+  @Test
+  public void shortDigestIsConsistent() {
+    assertHashFunctionAndMessageDigestEquivalentForInput("Bazel".getBytes(StandardCharsets.UTF_8));
+  }
+}