大厂测试都在用的Pytest技巧，面试加分项-平芜编程栈

01概述

pytest是一个非常成熟的全功能的Python测试框架，主要特点有以下几点：

简单灵活，容易上手，文档丰富；
支持参数化，可以细粒度地控制要测试的测试用例；
能够支持简单的单元测试和复杂的功能测试，还可以用来做selenium/appnium等自动化测试、接口自动化测试（pytest+requests）;
pytest具有很多第三方插件，并且可以自定义扩展，比较好用的如pytest-selenium（集成selenium）、pytest-html（完美html测试报告生成）、pytest-rerunfailures（失败case重复执行）、pytest-xdist（多CPU分发）等；
测试用例的skip和xfail处理；
可以很好的和CI工具结合，例如jenkins

02使用介绍

安装：pip install pytest

1、示例代码

编写规则：编写pytest测试样例非常简单，只需要按照下面的规则：

测试文件以test_开头（以_test结尾也可以）
测试类以Test开头，并且不能带有 init 方法
测试函数以test_开头
断言使用基本的assert即可

pytest1.py

fixture的scope参数

scope参数有四种，默认为function

function：每个test都运行，默认是function的scope
class：每个class的所有test只运行一次
module：每个module的所有test只运行一次
session：每个session只运行一次

setup和teardown操作

setup，在测试函数或类之前执行，完成准备工作，例如数据库链接、测试数据、打开文件等
teardown，在测试函数或类之后执行，完成收尾工作，例如断开数据库链接、回收内存资源等

备注：
也可以通过在fixture函数中通过yield实现setup和teardown功能

2、测试结果

如何执行

pytest # run all tests below current dir
pytest test_mod.py # run tests in module file test_mod.py
pytest somepath # run all tests below somepath like ./tests/
pytest -k stringexpr # only run tests with names that match the
# the "string expression", e.g. "MyClass and not method"
# will select TestMyClass.test_something
# but not TestMyClass.test_method_simple
pytest test_mod.py::test_func # only run tests that match the "node ID",
# e.g "test_mod.py::test_func" will be selected
# only run test_func in test_mod.py

通过pytest.mark对test方法分类执行

通过@pytest.mark控制需要执行哪些feature的test，例如在执行test前增加修饰@pytest.mark.website

通过 -m "website" 执行有website标记的test方法

$ pytest -v -m "website" pytest1.py
============================================================================== test session starts ===============================================================================platform linux2 --Python2.7.14, pytest-3.0.0, py-1.5.2, pluggy-0.3.1--/home/kevin/soft/anaconda2/bin/python
cachedir: .cacheUsing--randomly-seed=1522925202rootdir: /home/kevin/learn/python-web/tox/case2, inifile:plugins: randomly-1.0.0, mock-1.2, cov-2.0.0collected 3 items
pytest1.py::test_1 PASSED
============================================================================= pytest-warning summary =============================================================================WC1None pytest_funcarg__cov: declaring fixtures using "pytest_funcarg__" prefix is deprecated and scheduled to be removed in pytest 4.0. Please remove the prefix and use the @pytest.fixture decorator instead.===============================================================================2 tests deselected ==========================================================================================================================================1 passed, 2 deselected, 1 pytest-warnings in0.00 seconds ============================================================

通过 -m "not website" 执行没有website标记的test方法

$ pytest -v -m "not website" pytest1.py
============================================================================== test session starts ===============================================================================platform linux2 --Python2.7.14, pytest-3.0.0, py-1.5.2, pluggy-0.3.1--/home/kevin/soft/anaconda2/bin/python
cachedir: .cacheUsing
--randomly-seed=1522925192rootdir: /home/kevin/learn/python-web/tox/case2, inifile:plugins: randomly-1.0.0, mock-1.2, cov-2.0.0collected 3 items
pytest1.py::test_3 PASSED
pytest1.py::test_2 PASSED============================================================================= pytest-warning summary =============================================================================WC1None pytest_funcarg__cov: declaring fixtures using "pytest_funcarg__" prefix is deprecated and scheduled to be removed in pytest 4.0. Please remove the prefix and use the @pytest.fixture decorator instead.===============================================================================1 tests deselected ==========================================================================================================================================2 passed, 1 deselected, 1 pytest-warnings in0.00 seconds ============================================================

Console参数介绍

-v 用于显示每个测试函数的执行结果
-q 只显示整体测试结果
-s 用于显示测试函数中print()函数输出
-x, --exitfirst, exit instantly on first error or failed test
-h 帮助

Case 1

$ pytest -v pytest1.py
============================================================================== test session starts ===============================================================================
platform linux2 --Python2.7.14, pytest-3.0.0, py-1.5.2, pluggy-0.3.1--/home/kevin/soft/anaconda2/bin/python
cachedir: .cache
Using--randomly-seed=1522920341
rootdir: /home/kevin/learn/python-web/tox/case2, inifile:
plugins: randomly-1.0.0, mock-1.2, cov-2.0.0
collected 3 items
pytest1.py::test_1 PASSED
pytest1.py::test_3 PASSED
pytest1.py::test_2PASSED
============================================================================= pytest-warning summary =============================================================================WC1None pytest_funcarg__cov: declaring fixtures using "pytest_funcarg__" prefix is deprecated and scheduled to be removed in pytest 4.0. Please remove the prefix and use the @pytest.fixture decorator instead.==================================================================3 passed, 1 pytest-warnings in0.01 seconds ===================================================================

Case 2

$ pytest -s pytest1.py
============================================================================== test session starts ===============================================================================
platform linux2 --Python2.7.14, pytest-3.0.0, py-1.5.2, pluggy-0.3.1
Using --randomly-seed=1522920508
rootdir: /home/kevin/learn/python-web/tox/case2, inifile:
plugins: randomly-1.0.0, mock-1.2, cov-2.0.0
collected 3 items
pytest1.py setup_function called.Test_1
called..teardown_function called.setup_module called.Test_2 called..Test_3 called..teardown_module called.============================================================================= pytest-warning summary =============================================================================WC1None pytest_funcarg__cov: declaring fixtures using"pytest_funcarg__" prefix is deprecated and scheduled to be removed in pytest 4.0. Pleaseremove the prefix and use the @pytest.fixture decorator instead.==================================================================3 passed, 1 pytest-warnings in0.01 seconds ===================================================================

03扩展插件

测试报告

安装与样例

pipinstallpytest-cov # 计算pytest覆盖率，支持输出多种格式的测试报告
pytest --cov-report = html --cov = ./ test_code_target_dir

Console参数介绍

--cov=[path], measure coverage for filesystem path (multi-allowed)
指定被测试对象，用于计算测试覆盖率
--cov-report=type, type of report to generate: term, term-missing, annotate, html, xml (multi-allowed)
测试报告的类型
--cov-config=path, config file for coverage, default: .coveragerc, coverage
配置文件
--no-cov-on-fail, do not report coverage if test run fails, default: False
如果测试失败，不生成测试报告
--cov-fail-under=MIN, Fail if the total coverage is less than MIN.
如果测试覆盖率低于MIN，则认为失败

Console Result

---------------------------------------------------------------- coverage: platform linux2, python 2.7.14-final-0 ----------------------------------------------------------------
Name Stmts Miss Cover
--------------------------------
pytest1.py 18 0 100%

Html Result

测试顺序随机

pip install pytest-randomly

分布式测试

pip install pytest-xdist

出错立即返回

pip install pytest-instafail

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大厂测试都在用的Pytest技巧，面试加分项