def test_pngquant_should_optimize(self): optimizer = PngquantOptimizer(self.get_context()) temp = tempfile.NamedTemporaryFile() optimizer.optimize(None, fixtures_folder + '/img/bend.png', temp.name) self.assertLessEqual(os.path.getsize(temp.name), os.path.getsize(fixtures_folder + '/img/bend.png'), "pngquant could not lower filesize for img/bend.png")