rebaseline_server: display as much info as possible if expected/actual image is missing

gm/rebaseline_server/imagepair_test.py

 #!/usr/bin/python
 
 """
 Copyright 2014 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 Test imagepair.py
 """
@@ skipping 114 matching lines @@
                     'builder': 'MyBuilder',
                     'test': 'MyTest',
                 },
                 'imageAUrl':
                     'gradients_degenerate_2pt/10552995703607727960.png',
                 'imageBUrl':
                     'gradients_degenerate_2pt/11198253335583713230.png',
                 'isDifferent': True,
             },
         ],
+
+        # Test fix for http://skbug.com/2368 -- how do we handle an ImagePair
+        # missing one of its images?
+        [
+            # inputs:
+            'arcofzorro/16206093933823793653.png',
+            'nonexistentDir/111111.png',
+            {
+                'ignoreFailure': True,
+                'bugs': [1001, 1002],
+            },
+            {
+                'builder': 'MyBuilder',
+                'test': 'MyTest',
+            },
+            # expected output:
+            {
+                'expectations': {
+                    'bugs': [1001, 1002],
+                    'ignoreFailure': True,
+                },
+                'extraColumns': {
+                    'builder': 'MyBuilder',
+                    'test': 'MyTest',
+                },
+                'imageAUrl': 'arcofzorro/16206093933823793653.png',
+                'imageBUrl': 'nonexistentDir/111111.png',
+                'isDifferent': True,
+            },
+        ],
     ]
 
     db = imagediffdb.ImageDiffDB(self._temp_dir)
     for selftest in selftests:
       image_pair = imagepair.ImagePair(
           image_diff_db=db,
           base_url=IMG_URL_BASE,
           imageA_relative_url=selftest[0],
           imageB_relative_url=selftest[1],
           expectations=selftest[2],
           extra_columns=selftest[3])
       self.assertEqual(image_pair.as_dict(), selftest[4])
 
 
 def main():
   suite = unittest.TestLoader().loadTestsFromTestCase(ImagePairTest)
   unittest.TextTestRunner(verbosity=2).run(suite)
 
 
 if __name__ == '__main__':
   main()