pytest：通过夹具参数化测试用例

Question

你如何编写一个产生/返回参数化测试参数的夹具（一种方法）？

例如，我有一个测试如下：

@pytest.mark.parametrize(
    "input,expected", 
    [("hello", "hello"),
    ("world", "world")])
def test_get_message(self, input, expected):
    assert expected == MyClass.get_message(input)

我没有input并expected通过@pytest.mark.parametrize传递，而是对以下方法感兴趣：

@pytest.fixture(scope="session")
def test_messages(self):
    # what should I write here to return multiple 
    # test case with expected value for each?
    pass

def test_get_message(self, test_messages):
    expected = test_messages["expected"] # somehow extracted from test_messages?
    input = test_messages["input"]       # somehow extracted from test message?
    assert expected == MyClass.get_message(input)

Answer 1

要将参数移动到夹具中，您可以使用夹具参数：

@pytest.fixture(params=[("hello", "hello"),
    ("world", "world")], scope="session")
def test_messages(self, request):
    return request.param

def test_get_message(self, test_messages):
    input = test_messages[0]   
    expected = test_messages[1]
    assert expected == MyClass.get_message(input)

您还可以将参数放入单独的 function （与parametrize相同），例如

def get_test_messages():
    return [("hello", "hello"), ("world", "world")]

@pytest.fixture(params=get_test_messages(), scope="session")
def test_messages(self, request):
    return request.param

Answer 2

对我来说，您似乎想返回一个字典数组：

@pytest.fixture(scope="session")
def test_messages():
    return [
        {
            "input": "hello",
            "expected": "world"
        },
        {
            "input": "hello",
            "expected": "hello"
        }
    ]

要在测试用例中使用它，您需要遍历数组：

def test_get_message(self, test_messages):
    for test_data in test_messages:
        input = test_data["input"]
        expected = test_data["expected"]
        assert input == expected

但我不确定这是否是最好的方法，因为它仍然被认为只是一个测试用例，所以它只会在输出/报告中显示为一个测试用例。