diff --git a/src/test/java/com/google/devtools/build/lib/cmdline/LabelValidatorTest.java b/src/test/java/com/google/devtools/build/lib/cmdline/LabelValidatorTest.java
index feceda346d8205..9c16fb3fecf5b0 100644
--- a/src/test/java/com/google/devtools/build/lib/cmdline/LabelValidatorTest.java
+++ b/src/test/java/com/google/devtools/build/lib/cmdline/LabelValidatorTest.java
@@ -96,6 +96,7 @@ public void testValidateTargetName() throws Exception {
     assertNull(LabelValidator.validateTargetName("foo.bar"));
     assertNull(LabelValidator.validateTargetName("foo@bar"));
     assertNull(LabelValidator.validateTargetName("foo~bar"));
+    assertNull(LabelValidator.validateTargetName("foo#bar"));
 
     assertEquals("target names may not end with '/'",
                  LabelValidator.validateTargetName("foo/"));