apitrace diff-images: Print one line for each file being compared.

This is important so that the test suite can verify that "apitrace
diff-images" is actually doing something. The tricky case is when no
images are found to compare. In this case, diff-images exits with
value 0, (no differences), which is valid, but the test suite wants to
know that no comparison happened since that's unexpected, (and should
flag a failure in the test suite).

diff --git a/scripts/snapdiff.py b/scripts/snapdiff.py
index 61814d83c3de8ae546f118f4c9de0fbd4a7a547f..7ae3a433fa125724f83c82548bbff4da9e7886c8 100755 (executable)
--- a/scripts/snapdiff.py
+++ b/scripts/snapdiff.py
@@ -203,6 +203,7 @@ def main():
         root, ext = os.path.splitext(src_image)
         delta_image = "%s.diff.png" % (root, )
         if os.path.exists(ref_image) and os.path.exists(src_image):
+            print "Comparing %s and %s\n" % (ref_image, src_image)
             comparer = Comparer(ref_image, src_image, options.alpha)
             match = comparer.ae(fuzz=options.fuzz) == 0
             if match: