iOS自动化探索（四）自动化测试框架pytest

自动化测试框架 - pytest

pytest是Python最流行的单元测试框架之一, 帮助更便捷的编写测试脚本， 并支持多种功能复杂的测试场景， 能用来做app测试也能用作函数测试

官方文档: https://docs.pytest.org/en/latest/

pytest具有以下优点:

• 允许使用assert进行断言 
• 自动识别测试脚本、类、函数
• 可用于管理小型或者参数类型的测试数据或资源
• 兼容unittest和nose测试框架
• 支持Python2.7/Python3.4+
• 丰富的插件支持，超过315个插件支持

pytest安装

pip install -U pytest

如果提示下面的错误，说明是pip的版本太老了， 要更新下：

  Could not find a version that satisfies the requirement pytest (from versions: )
No matching distribution found for pytest

更新方式:

easy_install --upgrade pip

官方示例

准备一个test_sample.py, 内容如下：

def inc(x):
    return x + 1

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

在文件所在目录执行:

pytest

这里我们做下说明：

pytest脚本都以test_xxx.py为文件名；

inc方法是我们定义的一个自增函数，该函数将传递进来的参数加1后返回；

test_answer是我们编写的一个测试函数，其中我们使用基本的断言语句assert来对结果进行验证，测试函数以test_xxx作为命名

执行结果如下：

============================================================ test session starts ============================================================
platform darwin -- Python 2.7.15, pytest-4.1.0, py-1.7.0, pluggy-0.8.0
rootdir: /Users/jackey/Documents/iOS/code/iOS-Auto/Agent_Test, inifile:
collected 1 item                                                                                                                            

test_sample.py F                                                                                                                      [100%]

================================================================= FAILURES ==================================================================
________________________________________________________________ test_answer ________________________________________________________________

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

test_sample.py:5: AssertionError
========================================================= 1 failed in 0.05 seconds ==========================================================
(wda_python) bash-3.2$ 

当执行到assert inc(3) == 5时，报错

执行pytest会在当前目录和子目录中寻找test_xx.py的测试文件，并进入到测试文件中寻找test_xx开头的测试函数开始执行

执行pytest -q  test_xxx.py是执行执行的脚本

在看一个例子,测试指定错误： (Assert that a certain exception is raised)

import pytest

def f():
    raise SystemExit(1)

def test_mytest():
    with pytest.raises(SystemExit):
        f()

执行指令：

pytest -q test_sysexit.py

输出:

(wda_python) bash-3.2$ pytest -q test_sysexit.py 
.                                                                                                                                      [100%]
1 passed in 0.04 seconds
(wda_python) bash-3.2$ 

如果要开发多个测试方法，可以把方法写进一个class中

class TestClass(object):
    def test_one(self):
        x = 'this'
        assert 'h' in x

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

pytest能够自动识别类中的测试方法， 也不用我们去创建子类或者实实例, 运行结果如下：

(wda_python) bash-3.2$ pytest -q test_sample.py 
.F                                                                                                                                     [100%]
================================================================== FAILURES ==================================================================
_____________________________________________________________ TestClass.test_two _____________________________________________________________

self = <test_sample.TestClass object at 0x102e151d0>

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

test_sample.py:8: AssertionError
1 failed, 1 passed in 0.08 seconds
(wda_python) bash-3.2$ 

除了直接在脚本路径执行pytest外， 还可以用以下方式

python -m pytest xxx.py

出现第一个（或第N个）错误时停止

pytest -x            # stop after first failure
pytest --maxfail=2    # stop after two failures

运行执行测试脚本

pytest test_mod.py

运行指定目录下的所有脚本

pytest testing/

运行包含指定关键字的测试方法, 可以是文件名、类名、测试函数名

pytest -k "MyClass and not method"

执行node id运行测试脚本，每一个被收集的测试方法都会分配一个指定的id， 我们可以用一下方式运行执行的测试方法:

# To run a specific test within a module
pytest test_mod.py::test_func     

# To run a test within a class
pytest test_mod.py::TestClass::test_method

日志打印的不同方式

pytest --showlocals # show local variables in tracebacks
pytest -l           # show local variables (shortcut)

pytest --tb=auto    # (default) 'long' tracebacks for the first and last
                     # entry, but 'short' style for the other entries
pytest --tb=long    # exhaustive, informative traceback formatting
pytest --tb=short   # shorter traceback format
pytest --tb=line    # only one line per failure
pytest --tb=native  # Python standard library formatting
pytest --tb=no      # no traceback at all

测试报告

pytest默认是完整的测试报告， 我们可以加上-r标签显示简短测试报告，可再搭配一下参数

Here is the full list of available characters that can be used:

f - failed
E - error
s - skipped
x - xfailed
X - xpassed
p - passed
P - passed with output
a - all except pP

可以多个参数一起使用

Debug模式

pytest --pdb

示例:

(wda_python) bash-3.2$ pytest --pdb
========================================================== test session starts ===========================================================
platform darwin -- Python 2.7.15, pytest-4.1.0, py-1.7.0, pluggy-0.8.0
rootdir: /Users/jackey/Documents/iOS/code/iOS-Auto/Agent_Test, inifile:
collected 3 items                                                                                                                        

test_sample.py .F
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> traceback >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

self = <test_sample.TestClass object at 0x10e928610>

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

test_sample.py:8: AssertionError
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> entering PDB >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> /Users/jackey/Documents/iOS/code/iOS-Auto/Agent_Test/test_sample.py(8)test_two()
-> assert hasattr(x, 'check')
(Pdb) print x
hello
(Pdb) print hasattr(x,'check')
False
(Pdb) 

还可以指定第几次失败开始进入debug:

pytest -x --pdb   # drop to PDB on first failure, then end test session
pytest --pdb --maxfail=3  # drop to PDB for first three failures

任何失败的异常信息都会存储在sys.last_value，sys.last_type 以及 sys_last_traceback

在debug中可以通过以下方式获取最后报错的内容

(Pdb) import sys
(Pdb) sys.last_traceback.tb_lineno
1357
(Pdb) sys.last_value
AssertionError(u"assert False
 +  where False = hasattr('hello', 'check')",)
(Pdb) 

在执行一开始就进入到debug模式

pytest --trace

输入next执行下一步, exit退出

脚本中设置断点

import pdb

pdb.set_trace()

例如：

import pdb

class TestClass(object):
    def test_one(self):
        x = 'this'
        pdb.set_trace()
        assert 'h' in x

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

获取执行最慢的n个测试步骤

pytest --durations=10

======================================================= slowest 10 test durations ========================================================

(0.00 durations hidden.  Use -vv to show these durations.)

但如果所有脚本的运行时间都小于0.01s, 就不显示了， 除非带上-vv参数

pytest --durations=10 -vv

输出结果:

======================================================= slowest 10 test durations ========================================================
0.00s call     test_sample.py::TestClass::test_two
0.00s setup    test_sysexit.py::test_mytest
0.00s setup    test_sample.py::TestClass::test_two
0.00s setup    test_sample.py::TestClass::test_one
0.00s teardown test_sample.py::TestClass::test_two
0.00s teardown test_sample.py::TestClass::test_one
0.00s call     test_sysexit.py::test_mytest
0.00s teardown test_sysexit.py::test_mytest
0.00s call     test_sample.py::TestClass::test_one
=================================================== 1 failed, 2 passed in 0.06 seconds ===================================================
(wda_python) bash-3.2$ 

将日志保存到指定文件

pytest --resultlog=path

Disabling plugins

To disable loading specific plugins at invocation time, use the -p option together with the prefix no:.

Example: to disable loading the plugin doctest, which is responsible for executing doctest tests from text files, invoke pytest like this:

pytest -p no:doctest

我们也可以在pytestdemo脚本中去启动pytest:

import pytest

pytest.main()

执行python pytestdemo.py就可以执行pytest

main()不会抛出SystemExit的异常, 但会返回exitcode, 一共有6种exitcode

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

我们试着加上打印

import pytest

print pytest.main()

输出：

(wda_python) bash-3.2$ python pytestDemo.py 
========================================================== test session starts ===========================================================
platform darwin -- Python 2.7.15, pytest-4.1.0, py-1.7.0, pluggy-0.8.0
rootdir: /Users/jackey/Documents/iOS/code/iOS-Auto/Agent_Test, inifile:
collected 3 items                                                                                                                        

test_sample.py .F                                                                                                                  [ 66%]
test_sysexit.py .                                                                                                                  [100%]

================================================================ FAILURES ================================================================
___________________________________________________________ TestClass.test_two ___________________________________________________________

self = <test_sample.TestClass object at 0x1038ba650>

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

test_sample.py:11: AssertionError
=================================================== 1 failed, 2 passed in 0.05 seconds ===================================================
1
(wda_python) bash-3.2$ 

我们还可以在main中传递参数:

pytest.main(['-q','test_sample.py'])

给pytest.main添加plugin, 如下示例在执行的开头和结尾， 添加打印信息

import pytest

class MyPlugin(object):
    def pytest_sessionfinish(self):
        print '*** Test run reporting finishing'

    def pytest_sessionstart(self):
        print '*** Test run report beginning'

pytest.main(['-q','test_sample.py'], plugins=[MyPlugin()])

输出：

(wda_python) bash-3.2$ python pytestDemo.py
*** Test run report beginning
.F [100%]*** Test run reporting finishing

================================================================ FAILURES ================================================================
___________________________________________________________ TestClass.test_two ___________________________________________________________

self = <test_sample.TestClass object at 0x1090843d0>

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

test_sample.py:11: AssertionError
1 failed, 1 passed in 0.05 seconds