pytest参数化fixture复用及相似测试合并问题咨询

1. 让DELETE测试使用参数化fixture的方法 #

报错原因是test_register_delete_input没有添加@pytest.mark.parametrize装饰器，pytest会把username、password、message当成fixture去查找，自然找不到。解决方法有两种：

方法一：给DELETE测试单独添加参数化装饰器 #

直接给test_register_delete_input加上和POST测试一样的参数化装饰器即可：

@pytest.mark.parametrize(
    ("username", "password", "message"),
    (
        ("", "", b"Username is required."),
        ("a", "", b"Password is required."),
        ("test", "test", b"already registered"),
    ),
)
def test_register_delete_input(client, username, password, message):
    response = client.delete(
        "/register", data={"username": username, "password": password}
    )
    assert message in response.data

方法二：用测试类统一管理参数化 #

把两个测试放到同一个测试类中，将参数化装饰器加到类上，类内的所有测试方法都会自动继承该参数化配置：

@pytest.mark.parametrize(
    ("username", "password", "message"),
    (
        ("", "", b"Username is required."),
        ("a", "", b"Password is required."),
        ("test", "test", b"already registered"),
    ),
)
class TestRegisterValidation:
    def test_post_input(self, client, username, password, message):
        response = client.post(
            "/register", data={"username": username, "password": password}
        )
        assert message in response.data

    def test_delete_input(self, client, username, password, message):
        response = client.delete(
            "/register", data={"username": username, "password": password}
        )
        assert message in response.data

2. 合并两个测试的方案 #

完全可以合并成一个测试，只需要把请求方法也加入参数化项中，让一个测试函数覆盖两种请求类型：

方式一：直接扩展参数化列表 #

把POST和DELETE对应的测试用例都列在参数化里：

@pytest.mark.parametrize(
    ("method", "username", "password", "message"),
    (
        ("post", "", "", b"Username is required."),
        ("post", "a", "", b"Password is required."),
        ("post", "test", "test", b"already registered"),
        ("delete", "", "", b"Username is required."),
        ("delete", "a", "", b"Password is required."),
        ("delete", "test", "test", b"already registered"),
    ),
)
def test_register_input_validation(client, method, username, password, message):
    # 通过getattr获取client对应的请求方法
    response = getattr(client, method)(
        "/register", data={"username": username, "password": password}
    )
    assert message in response.data

方式二：用itertools.product简化参数化 #

如果用户数据是重复的，可以用itertools.product来组合请求方法和用户数据，避免重复写测试用例：

from itertools import product

# 定义共用的用户测试数据
REGISTER_TEST_CASES = (
    ("", "", b"Username is required."),
    ("a", "", b"Password is required."),
    ("test", "test", b"already registered"),
)

@pytest.mark.parametrize(
    ("method", "username", "password", "message"),
    # 组合请求方法和测试数据，生成所有可能的用例
    product(("post", "delete"), REGISTER_TEST_CASES),
)
def test_register_input_validation(client, method, username, password, message):
    response = getattr(client, method)(
        "/register", data={"username": username, "password": password}
    )
    assert message in response.data

内容的提问来源于stack exchange，提问作者reach jaango