def test_output_diffs(self):
        # Test to ensure that we don't generate -pretty.html if PrettyPatch isn't available.
        host = MockHost()
        _, err, _ = logging_run(['--pixel-tests', 'failures/unexpected/text-image-checksum.html'], tests_included=True, host=host)
        written_files = host.filesystem.written_files
        self.assertTrue(any(path.endswith('-diff.txt') for path in written_files.keys()))
        self.assertFalse(any(path.endswith('-pretty-diff.html') for path in written_files.keys()))

        full_results_text = host.filesystem.read_text_file('/tmp/layout-test-results/full_results.json')
        full_results = json.loads(full_results_text.replace("ADD_RESULTS(", "").replace(");", ""))
        self.assertEqual(full_results['has_pretty_patch'], False)

    def rmtree(self, path):
        if not path.endswith(self.sep):
            path += self.sep

        for f in self.files:
            if f.startswith(path):
                self.files[f] = None

 def normpath(self, path):
     # This function is called a lot, so we try to optimize the common cases
     # instead of always calling _slow_but_correct_normpath(), above.
     if '..' in path or '/./' in path:
         # This doesn't happen very often; don't bother trying to optimize it.
         return self._slow_but_correct_normpath(path)
     if not path:
         return '.'
     if path == '/':
         return path
     if path == '/.':
         return '/'
     if path.endswith('/.'):
         return path[:-2]
     if path.endswith('/'):
         return path[:-1]
     return path

    def isdir(self, path):
        if path in self.files:
            return False
        if not path.endswith(self.sep):
            path += self.sep

        # We need to use a copy of the keys here in order to avoid switching
        # to a different thread and potentially modifying the dict in
        # mid-iteration.
        files = self.files.keys()[:]
        return any(f.startswith(path) for f in files)

 def abspath(self, path):
     if path.endswith(self.sep):
         return path[:-1]
     return path