def METHOD_NAME(self):
    test_data = zip(dishes_and_overlap, singletons)
    for variant, (item, result) in enumerate(test_data, start=1):
        with self.subTest(f"variation #{variant}", inputs="overlapping ingredients",
                          results="ingredients in only one dish"):
            error_message = ("Expected only ingredients that belong to exactly "
                            "one dish, but got multi-dish ingredients instead.")
            self.assertEqual(singleton_ingredients(item[0], item[1]), (result), msg=error_message)