new file mode 100644
--- /dev/null
+++ b/graphdiff.py
@@ -0,0 +1,59 @@
+import json
+import difflib
+import re
+
+def tests_only(graph):
+    return {l: t for l, t in graph.iteritems()
+            if t['attributes'].get('legacy_kind', '').endswith('test') or t['attributes']['kind'] in ('desktop-test', 'android-test', 'test')}
+
+def replace_labels(str):
+    return re.sub("<[^>]*>", "<...>", str)
+
+def drop_stuff(graph):
+    for t in graph.itervalues():
+        del t['label']
+        del t['attributes']['kind']
+        del t['task']['metadata']
+    return graph
+
+def relabel(graph):
+    rv = {}
+    for l, t in graph.iteritems():
+        if l.startswith('android-test-') or l.startswith('desktop-test-'):
+            l = l[8:]
+        if l in rv:
+            raise Exception("duplicate label %s for %s / %s" % (l, t['label'], rv[l]['label']))
+        rv[l] = t
+    return rv
+
+def main():
+    graph1 = json.load(open("before"))
+    graph2 = json.load(open("after"))
+
+    graph1 = drop_stuff(relabel(tests_only(graph1)))
+    graph2 = drop_stuff(relabel(tests_only(graph2)))
+
+    print("comparing {} and {} tasks".format(len(graph1), len(graph2)))
+
+    only1 = set(graph1) - set(graph2)
+    only2 = set(graph2) - set(graph1)
+    for task in sorted(only1 | only2):
+        if task in only1:
+            print "-" + task
+            del graph1[task]
+        else:
+            print "+" + task
+            del graph2[task]
+
+    graph1 = replace_labels(json.dumps(graph1, indent=4, sort_keys=True)).split('\n')
+    graph2 = replace_labels(json.dumps(graph2, indent=4, sort_keys=True)).split('\n')
+
+    diff = False
+    for line in difflib.unified_diff(graph1, graph2, fromfile="before", tofile="after", lineterm='', n=4):
+        diff = True
+        print line
+
+    if not diff:
+        print("no diff")
+
+main()