diff --git a/gerrit-server/src/test/java/com/google/gerrit/testutil/GerritBaseTests.java b/gerrit-server/src/test/java/com/google/gerrit/testutil/GerritBaseTests.java
index 4ba5d3a..44e5d74 100644
--- a/gerrit-server/src/test/java/com/google/gerrit/testutil/GerritBaseTests.java
+++ b/gerrit-server/src/test/java/com/google/gerrit/testutil/GerritBaseTests.java
@@ -33,7 +33,12 @@
 
   protected String getSanitizedMethodName() {
     String name = testName.getMethodName().toLowerCase();
-    name = CharMatcher.javaLetterOrDigit().negate().replaceFrom(name, '_');
+    name =
+        CharMatcher.inRange('a', 'z')
+            .or(CharMatcher.inRange('A', 'Z'))
+            .or(CharMatcher.inRange('0', '9'))
+            .negate()
+            .replaceFrom(name, '_');
     name = CharMatcher.is('_').trimTrailingFrom(name);
     return name;
   }