pytest合集（3）— 测试用例

一、测试用例编写规范

• 测试文件名必须以“test_”开头或者以”_test”结尾
• 测试类命名以Test开头
• 测试方法必须以“test_”开头
• 测试用例包pakege必须要有__init__.py文件
• 使用assert断言

二、测试用例收集规则

Conventions for Python test discovery

pytest implements the following standard test discovery:

• If no arguments are specified then collection starts from testpaths (if configured) or the current directory. Alternatively, command line arguments can be used in any combination of directories, file names or node ids.

• Recurse into directories, unless they match norecursedirs.

• In those directories, search for test_*.py or *_test.py files, imported by their test package name.

• From those files, collect test items:

  • test prefixed test functions or methods outside of class

  • test prefixed test functions or methods inside Test prefixed test classes (without an __init__ method)

For examples of how to customize your test discovery Changing standard (Python) test discovery.

Within Python modules, pytest also discovers tests using the standard unittest.TestCase subclassing technique.

说明：

（1）未指定参数，pytest会从当前目录及其子目录下所有以test_*.py或*_test.py文件中，收集以"test_"开头的函数。

（2）命令行参数可以在目录、文件名或节点ID的任意组合中使用。

（3）可以读取pytest.ini配置文件。

（4）兼容unittest的测试用例。

三、测试用例执行顺序

 （1）编写测试用例文件 test_class.py和test_sample.py如下：

# content of test_sample.py
def func(x):
    return x + 1


def test_answer():
    assert func(3) == 5

# content of test_class.py
class TestClass:
    def test_one(self):
        x = "this"
        assert "h" in x

    def test_two(self):
        x = "hello"
        assert hasattr(x, "check")

 测试用例目录结构如下：

（2）执行测试用例

 

Microsoft Windows [版本 10.0.19044.1766]
(c) Microsoft Corporation。保留所有权利。

(venv) C:\Users\057776\PycharmProjects\pytest-demo>pytest
================================ test session starts ================================
platform win32 -- Python 3.8.8, pytest-6.2.3, py-1.10.0, pluggy-0.13.1
rootdir: C:\Users\057776\PycharmProjects\pytest-demo
plugins: html-3.1.1, metadata-1.11.0, rerunfailures-9.1.1, assume-2.2.0, requests-mock-1.7.0
collected 3 items                                                                                                                                                   

testcases\test_class.py .F                                                                                                                                    [ 66%]
testcases\test_sample.py F                                                                                                                                    [100%]

=================================== FAILURES ===================================
__________________________________ TestClass.test_two __________________________________

self = <testcases.test_class.TestClass object at 0x000001A6855B9400>

    def test_two(self):
        x = "hello"
>       assert hasattr(x, "check")
E       AssertionError: assert False
E        +  where False = hasattr('hello', 'check')

testcases\test_class.py:20: AssertionError
____________________________________ test_answer ____________________________________

    def test_answer():
>       assert func(3) == 5
E       assert 4 == 5
E        +  where 4 = func(3)

testcases\test_sample.py:18: AssertionError
=============================== short test summary info ===============================
FAILED testcases/test_class.py::TestClass::test_two - AssertionError: assert False
FAILED testcases/test_sample.py::test_answer - assert 4 == 5
============================== 2 failed, 1 passed in 0.51s ==============================

(venv) C:\Users\057776\PycharmProjects\pytest-demo>
 

collected 3 items  ：

分析运行结果可知，根据测试用例收集规则，一共收集到了3条测试用例，分别对应 testcases\test_class.py 和 testcases\test_sample.py 文件中的 3个函数 test_one，test_two，test_answer。

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reference：

Get Started — pytest documentation