pytest 单元测试

pytest简介

pytest 是python的一种单元测试框架，它非常的简洁、清晰。

pytest 安装

pip install -U pytest

查看pytest版本

pytest --version

入门

创建、运行第一个 test

test_first.py

def inc(x):

    return x + 1

def test_inc():

    assert inc(10) == 20

运行 pytest

an@hosta:~/PycharmProjects/testproject/pytest_study$ pytest     # 运行命令

========================================================== test session starts ==========================================================

platform linux -- Python 3.5.2, pytest-3.3.2, py-1.5.2, pluggy-0.6.0

rootdir: /home/an/PycharmProjects/testproject/pytest_study, inifile: pytest.ini

plugins: xdist-1.22.0

collected 1 item      # 搜集到的测试用例数量                                                                                                                

test_cont.py F   # F 代表测试出错，                                                                                                                 [100%]  # 测试完成率

=============================================================== FAILURES ================================================================

_______________________________________________________________ test_inc ____________________ # 测试模块名     _______________________________________

    def test_inc():

>       assert inc(10) == 20   # 报错的位置

E       assert 11 == 20   # 报错原因

E        +  where 11 = inc(10)   # 错误的来源

test_cont.py:6: AssertionError

======================================================= 1 failed in 0.04 seconds =============# 测试结果  =======================================

pytest 测试代码中抛出的异常

cont_test.py

import pytest

def inc(x):

    return x + 1

def test_inc():

    assert inc(10) == 11

def f():

    raise SyntaxError()

def test_f():

    with pytest.raises(SyntaxError):

        f()

运行pytest

an@hosta:~/PycharmProjects/testproject/pytest_study$ pytest

========================================================== test session starts ==========================================================

platform linux -- Python 3.5.2, pytest-3.3.2, py-1.5.2, pluggy-0.6.0

rootdir: /home/an/PycharmProjects/testproject/pytest_study, inifile: pytest.ini

plugins: xdist-1.22.0

collected 2 items   # 两个测试用例                                                                                                                      

cont_test.py ..        # 两个 . 表示都测试成功了       F 表示失败                                                                                                    [100%]

======================================================= 2 passed in 0.01 seconds ========= #测试结果  =======================================

另一种方式运行多个测试。构造一个测试类里面包含多个测试用例

cont_test.py

import pytest

class TestClass:

    def test_one(self):

        x = "this"

        assert x != "that"

    def test_two(self):

        x = "hello"

        assert hasattr(x, "upper")

    def test_three(self):

        with pytest.raises(IndexError):

            raise IndexError

运行 pytest

运行pytest的退出码

Exit code 0:	All tests were collected and passed successfully

Exit code 1:	Tests were collected and run but some of the tests failed

Exit code 2:	Test execution was interrupted by the user

Exit code 3:	Internal error happened while executing tests

Exit code 4:	pytest command line usage error

Exit code 5:	No tests were collected

指定测试用例失败次数失败之后，就停止测试

pytest -x 在第一次失败之后，就停止运行剩余的测试

pytest --maxfail=2 两次失败之后，就停止运行剩余测试

指定运行测试用例

目录结构

|---pytest_test

        |

        |---cont_test.py

# 模块内容

cont_test.py

import pytest

def inc(x):

    return x + 1

def test_inc():

    assert inc(10) == 11

def f():

    raise SyntaxError()

@pytest.mark.slow

def test_f():

    with pytest.raises(SyntaxError):

        f()

class TestClass:

    def test_one(self):

        x = "t"

        assert x == "that"

    def test_two(self):

        x = "hello"

        assert hasattr(x, "pper")

    def test_three(self):

        with pytest.raises(IndexError):

            raise IndexError

指定运行目录

pytest pytest_test
自动搜索运行本目录内的测试模块（以test开头或结尾）

pytest_test$ pytest
指定运行模块

pytest_test$ pytest cont_test.py
指定测试函数

pytest_test$ pytest cont_test.py::test_inc
指定测试类

pytest_test$ pytest cont_test.py::TestClass
指定测试方法

pytest_test$ pytest cont_test.py::TestClass::test_one
指定被mark的测试

pytest_test$ pytest -m slow

将结果输出到 XML 文件

pytest --junitxml=/tmp/zz.xml

禁用pytest的扩展

pytest -p no:doctest -p no:django

方法二：

创建一个 pytest.ini 文件

pytest.ini

[pytest]

addopts = -p no:django -p no:forked -p no:xdist-1.22.0 -p no:celery

;禁用扩展

异常

捕获程序中故意引发的异常

def f():

    raise SyntaxError()

def test_f():

    with pytest.raises(SyntaxError):

        f()

指定测试失败的信息

def test_f():

    with pytest.raises(SyntaxError, message='this is i expected error'):

        pass

——————————————————————————————

------------------------------------------------ generated xml file: /home/an/haha.xml -------------------------------------------------

=============================================================== FAILURES ================================================================

________________________________________________________________ test_f _________________________________________________________________

    def test_f():

        with pytest.raises(SyntaxError, message='this is i expected error'):

>           pass

E           Failed: this is i expected error  # 正是我们所希望失败

cont_test.py:17: Failed

================================================== 1 failed, 3 passed in 0.06 seconds =====

进一步限定我们所期望的异常，match使用的 python 中 re.search 方法进行匹配

def test_f():

    with pytest.raises(ValueError, match=r'.?1'):

        raise ValueError("a1")

# 正常



def test_f():

    with pytest.raises(ValueError, match=r'.?1'):

        raise ValueError("z3")

_____________________________________________

============================================================== FAILURES ================================================================

________________________________________________________________ test_f _________________________________________________________________

    def test_f():

        with pytest.raises(ValueError, match=r'.?1'):

>           raise ValueError("z3")

E           ValueError: z3

cont_test.py:17: ValueError

During handling of the above exception, another exception occurred:

    def test_f():

        with pytest.raises(ValueError, match=r'.?1'):

>           raise ValueError("z3")

E           AssertionError: Pattern '.?1' not found in 'z3'    # 匹配失败

cont_test.py:17: AssertionError

================================================== 1 failed, 3 passed in 0.10 seconds ============

巴特西