Improve run-webkit-tests error reporting when ref tests have missing images.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/controllers/test_result_writer_unittest.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 61 matching lines @@
         failure = test_failures.FailureReftestMismatch()
         failure.reference_filename = 'notfound.html'
         written_files = self.run_test(failures=[failure], files={})
         self.assertEqual(written_files, {})
 
         failure = test_failures.FailureReftestMismatchDidNotOccur()
         failure.reference_filename = 'notfound.html'
         written_files = self.run_test(failures=[failure], files={})
         self.assertEqual(written_files, {})
 
+    def test_reftest_image_missing(self):
+        failure = test_failures.FailureReftestNoImageGenerated()
+        failure.reference_filename = '/src/exists-expected.html'
+        files = {'/src/exists-expected.html': 'yup'}
+        written_files = self.run_test(failures=[failure], files=files)
+        self.assertEqual(written_files, {'/tmp/exists-expected.html': 'yup'})
+
+        failure = test_failures.FailureReftestNoReferenceImageGenerated()
+        failure.reference_filename = '/src/exists-expected.html'
+        files = {'/src/exists-expected.html': 'yup'}
+        written_files = self.run_test(failures=[failure], files=files)
+        self.assertEqual(written_files, {'/tmp/exists-expected.html': 'yup'})
+
     def test_baseline_name(self):
         fs = MockFileSystem()
         self.assertEqual(baseline_name(fs, 'x/y/foo.html', 'txt'), 'x/y/foo-expected.txt')
         self.assertEqual(baseline_name(fs, 'foo.html', 'txt'), 'foo-expected.txt')
         self.assertEqual(baseline_name(fs, 'foo', 'txt'), 'foo-expected.txt')