Open source most of our docgen tests.

--
MOS_MIGRATED_REVID=110746503
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java b/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
index 9278dd3..701487f 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
@@ -72,4 +72,7 @@
   public static final String TOOLS_REPOSITORY = "@bazel_tools";
 
   public static final String TOOLS_REPOSITORY_PATH = "tools/cpp";
+
+  public static final ImmutableList<String> DOCS_RULES_PATHS = ImmutableList.of(
+      "src/main/java/com/google/devtools/build/lib/rules");
 }