1 files changed, 35 insertions, 0 deletions
diff --git a/testing/web-platform/tests/diff-manifest.py b/testing/web-platform/tests/diff-manifest.py
new file mode 100755
index 000000000..801733cc6
--- /dev/null
+++ b/testing/web-platform/tests/diff-manifest.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+
+import difflib
+import json
+import os
+import subprocess
+import sys
+
+
+def call(*args):
+    return subprocess.check_output(args)
+
+
+def get_manifest(rev):
+    call("git", "checkout", rev)
+    call("./manifest", "-r")
+    with open("MANIFEST.json", "r") as fp:
+        return fp.readlines()
+
+
+def main():
+    after = get_manifest("HEAD")
+
+    call("git", "fetch", "origin", "master:master")
+    merge_base = call("git", "merge-base", "master", "HEAD").strip()
+    before = get_manifest(merge_base)
+
+    diff = difflib.unified_diff(before, after,
+                                fromfile='before.json', tofile='after.json')
+    for line in diff:
+        sys.stdout.write(line)
+
+
+if __name__ == "__main__":
+    main()