CS50P中test_twttr练习的pytest无测试运行问题排查

我正在学习CS50P旁听版本，在test_twttr练习里对pytest的使用感到困惑。主程序功能是移除字符串中的元音，我写了测试代码，但运行pytest时始终返回“no test ran”，课程检查工具首项检查也报错——正常功能正常的话应该无错误提示。请问我在pytest使用上漏了什么？

测试代码：

from twttr import shorten

def main():
    upperV()
    lowerV()
    number()
    symbol()

def upperV():
    assert shorten("sAo") == "so"
    assert shorten("sEo") == "so"
    assert shorten("sIo") == "so"
    assert shorten("sOo") == "so"
    assert shorten("sUo") == "so"

def lowerV():
    assert shorten("sao") == "so"
    assert shorten("seo") == "so"
    assert shorten("sio") == "so"
    assert shorten("soo") == "so"
    assert shorten("suo") == "so"

def number():
    assert shorten("s1o") == "s1o"
    assert shorten("s0o") == "s0o"
    assert shorten("s2o") == "s2o"
    assert shorten("s4o") == "s4o"
    assert shorten("s5o") == "s5o"
def space():
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
def symbol():
    assert shorten("s@o") == "s@o"
    assert shorten("s#o") == "s#o"

if __name__ == "__main__":
    main()

问题原因及解决方法 #

pytest识别测试用例有固定规则，你的代码不符合这些规则，导致它找不到要运行的测试：

• 测试函数命名不符合规范：pytest默认只会识别以test_开头的函数作为测试用例，你的函数名是upperV、lowerV这类，pytest不会把它们当成测试函数。
• 测试文件命名需注意：确保你的测试文件命名是test_*.py格式（比如test_twttr.py），pytest只会自动发现这类命名的文件里的测试。

修改后的测试代码示例：

from twttr import shorten

def test_upper_vowels():
    assert shorten("sAo") == "so"
    assert shorten("sEo") == "so"
    assert shorten("sIo") == "so"
    assert shorten("sOo") == "so"
    assert shorten("sUo") == "so"

def test_lower_vowels():
    assert shorten("sao") == "so"
    assert shorten("seo") == "so"
    assert shorten("sio") == "so"
    assert shorten("soo") == "so"
    assert shorten("suo") == "so"

def test_numbers():
    assert shorten("s1o") == "s1o"
    assert shorten("s0o") == "s0o"
    assert shorten("s2o") == "s2o"
    assert shorten("s4o") == "s4o"
    assert shorten("s5o") == "s5o"

def test_spaces():
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"
    assert shorten("s o") == "s o"

def test_symbols():
    assert shorten("s@o") == "s@o"
    assert shorten("s#o") == "s#o"

另外，不需要写main()函数和if __name__ == "__main__"的执行逻辑，pytest会自动遍历并运行所有符合规则的测试函数。

内容的提问来源于stack exchange，提问作者AGhoul