--- a/tests/test-run-tests.t	Mon Jul 06 23:23:22 2015 -0400
+++ b/tests/test-run-tests.t	Fri Jul 03 06:56:03 2015 +0900
@@ -566,3 +566,20 @@
 
   $ rm -f test-glob-backslash.t
 
+Test reusability for third party tools
+======================================
+
+  $ mkdir "$TESTTMP"/anothertests
+  $ cd "$TESTTMP"/anothertests
+
+test that `run-tests.py` can execute hghave, even if it runs not in
+Mercurial source tree.
+
+  $ cat > test-hghave.t <<EOF
+  > #require true
+  >   $ echo foo
+  >   foo
+  > EOF
+  $ run-tests.py test-hghave.t
+  .
+  # Ran 1 tests, 0 skipped, 0 warned, 0 failed.