diff --git a/build_tools/format-diff.sh b/build_tools/format-diff.sh
index e8c2800f5..470bad94b 100755
--- a/build_tools/format-diff.sh
+++ b/build_tools/format-diff.sh
@@ -109,6 +109,11 @@ then
   # Use master branch from that remote
   [ "$FORMAT_UPSTREAM" ] || FORMAT_UPSTREAM="$FORMAT_REMOTE/master"
   echo FORMAT_UPSTREAM is $FORMAT_UPSTREAM
+  echo CLANG_FORMAT_DIFF is $CLANG_FORMAT_DIFF
+  if [ -f ./clang-format-diff.py]
+  then
+    echo found file
+  fi
   # Get the common ancestor with that remote branch. Everything after that
   # common ancestor would be considered the contents of a pull request, so
   # should be relevant for formatting fixes.