Pytest单元测试系列[v1.0.0][编写测试函数]
一个规范的测试方法一定带有断言，在使用pytest时，可以直接使用Python自带的assert关键字
| Pytest | Unittest |
|---|---|
| assert something | assertTrue(something) |
| assert a==b | assertEqual(a,b) |
| assert a<=b | assertLessEqual(a,b) |
| … | … |
Pytest允许在assert关键字添加任意表达式，表达式的值通过bool转换后等于False则表示断言失败，测试用例执行失败；如果等于True则表示断言成功，测试用例执行成功。
重写assert
pytest可以重写assert关键字，它可以截断对原生assert的调用，替换为pytest定义的assert，从而展示更详细的信息和细节。
from collections import namedtuple
Task = namedtuple('Task', ['summary','owner','done','id'])
# __new__.__defaults__创建默认的Task对象
Task.__new__.__defaults__ = (None, None, False, None)
import pytest
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
assert t1 == t2
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
assert t1_dict == t2_dict
执行结果如下：
E:\Programs\Python\Python_Pytest\TestScripts>pytest test_three.py
=========================================== test session starts ==============================================
platform win32 -- Python 3.7.3, pytest-4.5.0, py-1.8.0, pluggy-0.11.0
rootdir: E:\Programs\Python\Python_Pytest\TestScripts
plugins: xdist-1.29.0, timeout-1.3.3, repeat-0.8.0, instafail-0.4.1, forked-1.0.2, emoji-0.2.0, allure-pytest-2.6.3
collected 2 items
test_three.py FF [100%]
================================================ FAILURES ====================================================
___________________________________________ test_task_equality _______________________________________________
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
> assert t1 == t2
E AssertionError: assert Task(summary=...alse, id=None) == Task(summary='...alse, id=None)
E At index 0 diff: 'sit there' != 'do something'
E Use -v to get the full diff
test_three.py:14: AssertionError
---------------------------------------- Captured stdout call ------------------------------------------------
Task(summary='sit there', owner='brain', done=False, id=None)
Task(summary='do something', owner='okken', done=False, id=None)
___________________________________________ test_dict_equal __________________________________________________
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
> assert t1_dict == t2_dict
E AssertionError: assert OrderedDict([...('id', None)]) == OrderedDict([(...('id', None)])
E Omitting 3 identical items, use -vv to show
E Differing items:
E {'owner': 'okken'} != {'owner': 'okkem'}
E Use -v to get the full diff
test_three.py:22: AssertionError
------------------------------------------- Captured stdout call ---------------------------------------------
OrderedDict([('summary', 'make sandwich'), ('owner', 'okken'), ('done', False), ('id', None)])
OrderedDict([('summary', 'make sandwich'), ('owner', 'okkem'), ('done', False), ('id', None)])
========================================== 2 failed in 0.20 seconds===========================================
加上参数-v，执行结果如下：
E:\Programs\Python\Python_Pytest\TestScripts>pytest test_three.py -v
=========================================== test session starts ==============================================
platform win32 -- Python 3.7.3, pytest-4.5.0, py-1.8.0, pluggy-0.11.0 -- c:\python37\python.exe
cachedir: .pytest_cache
rootdir: E:\Programs\Python\Python_Pytest\TestScripts
plugins: xdist-1.29.0, timeout-1.3.3, repeat-0.8.0, instafail-0.4.1, forked-1.0.2, emoji-0.2.0, allure-pytest-2.6.3
collected 2 items
test_three.py::test_task_equality FAILED [ 50%]
test_three.py::test_dict_equal FAILED [100%]
================================================ FAILURES ===================================================
___________________________________________ test_task_equality ______________________________________________
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
> assert t1 == t2
E AssertionError: assert Task(summary=...alse, id=None) == Task(summary='...alse, id=None)
E At index 0 diff: 'sit there' != 'do something'
E Full diff:
E - Task(summary='sit there', owner='brain', done=False, id=None)
E ? ^^^ ^^^ ^^^^
E + Task(summary='do something', owner='okken', done=False, id=None)
E ? +++ ^^^ ^^^ ^^^^
test_three.py:14: AssertionError
----------------------------------------- Captured stdout call -----------------------------------------------
Task(summary='sit there', owner='brain', done=False, id=None)
Task(summary='do something', owner='okken', done=False, id=None)
___________________________________________ test_dict_equal __________________________________________________
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
> assert t1_dict == t2_dict
E AssertionError: assert OrderedDict([...('id', None)]) == OrderedDict([(...('id', None)])
E Omitting 3 identical items, use -vv to show
E Differing items:
E {'owner': 'okken'} != {'owner': 'okkem'}
E Full diff:
E OrderedDict([('summary', 'make sandwich'),
E - ('owner', 'okken'),
E ? ^...
E
E ...Full output truncated (5 lines hidden), use '-vv' to show
test_three.py:22: AssertionError
-------------------------------------------- Captured stdout call --------------------------------------------
OrderedDict([('summary', 'make sandwich'), ('owner', 'okken'), ('done', False), ('id', None)])
OrderedDict([('summary', 'make sandwich'), ('owner', 'okkem'), ('done', False), ('id', None)])
========================================== 2 failed in 0.13 seconds ==========================================
预期异常
"""
在Task项目的API中，有几个地方可能抛出异常
def add(task): # type:(Task) ->int
def get(task_id): # type:(int) ->Task
def list_tasks(owner=None): # type:(str|None) ->list of task
def count(): # type:(None) ->int
def update(task_id, task): # type:(int, Task) ->None
def delete(task_id): # type:(int) ->None
def delete_all(): # type:() ->None
def unique_id(): # type:() ->int
def start_tasks_db(db_path, db_type): # type:(str, str) ->None
def stop_tasks_db(): # type:() ->None
"""
import pytest
import tasks
def test_add_raises():
with pytest.raises(TypeError):
tasks.add(task='no a Task object')
"""
测试用例中有with pytest.raise(TypeError)生命，意味着无论with结构中的内容是什么
都至少会发生TypeError异常，如果测试通过，说明确实发生了我们预期TypeError，如果抛出的是其他类型的异常
则与我们预期的异常不一致，测试用例执行失败
"""
def test_start_tasks_db_raises():
with pytest.raises(ValueError) as excinfo:
tasks.start_tasks_db('some/great/path', 'mysql')
exception_msg = excinfo.value.args[0]
assert exception_msg == "db_type must be a 'tiny' or 'mongo' "
测试函数的标记
from collections import namedtuple
import pytest
Task = namedtuple('Task', ['summary','owner','done','id'])
# __new__.__defaults__创建默认的Task对象
Task.__new__.__defaults__ = (None, None, False, None)
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
assert t1 == t2
@pytest.mark.dict
@pytest.mark.smoke
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
assert t1_dict == t2_dict
执行结果如下：
E:\Programs\Python\Python_Pytest\TestScripts>pytest -v -m 'smoke' test_five.py
======================================== test session starts =================================================
platform win32 -- Python 3.7.3, pytest-4.5.0, py-1.8.0, pluggy-0.11.0 -- c:\python37\python.exe
cachedir: .pytest_cache
rootdir: E:\Programs\Python\Python_Pytest\TestScripts
plugins: xdist-1.29.0, timeout-1.3.3, repeat-0.8.0, instafail-0.4.1, forked-1.0.2, emoji-0.2.0, allure-pytest-2.6.3
collected 2 items
test_five.py::test_task_equality FAILED [ 50%]
test_five.py::test_dict_equal FAILED [100%]
================================================ FAILURES ====================================================
__________________________________________ test_task_equality ________________________________________________
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
> assert t1 == t2
E AssertionError: assert Task(summary=...alse, id=None) == Task(summary='...alse, id=None)
E At index 0 diff: 'sit there' != 'do something'
E Full diff:
E - Task(summary='sit there', owner='brain', done=False, id=None)
E ? ^^^ ^^^ ^^^^
E + Task(summary='do something', owner='okken', done=False, id=None)
E ? +++ ^^^ ^^^ ^^^^
test_five.py:14: AssertionError
--------------------------------------- Captured stdout call -------------------------------------------------
Task(summary='sit there', owner='brain', done=False, id=None)
Task(summary='do something', owner='okken', done=False, id=None)
___________________________________________ test_dict_equal __________________________________________________
@pytest.mark.dict
@pytest.mark.smoke
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
> assert t1_dict == t2_dict
E AssertionError: assert OrderedDict([...('id', None)]) == OrderedDict([(...('id', None)])
E Omitting 3 identical items, use -vv to show
E Differing items:
E {'owner': 'okken'} != {'owner': 'okkem'}
E Full diff:
E OrderedDict([('summary', 'make sandwich'),
E - ('owner', 'okken'),
E ? ^...
E
E ...Full output truncated (5 lines hidden), use '-vv' to show
test_five.py:24: AssertionError
--------------------------------------- Captured stdout call -------------------------------------------------
OrderedDict([('summary', 'make sandwich'), ('owner', 'okken'), ('done', False), ('id', None)])
OrderedDict([('summary', 'make sandwich'), ('owner', 'okkem'), ('done', False), ('id', None)])
============================================ warnings summary ================================================
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.smoke - is this a typo? You can register custom marks to avoi
d this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.dict - is this a typo? You can register custom marks to avoid
this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
-- Docs: https://docs.pytest.org/en/latest/warnings.html
=================================== 2 failed, 2 warnings in 0.22 seconds =====================================
在命令行执行使用了 -m marker_name参数，pytest在执行时会自动寻找被标记为marker_name的测试方法去执行，同时-m还支持and、or、not关键字，如下方式：
E:\Programs\Python\Python_Pytest\TestScripts>pytest -v -m "smoke and not dict" test_five.py
========================================= test session starts ================================================
platform win32 -- Python 3.7.3, pytest-4.5.0, py-1.8.0, pluggy-0.11.0 -- c:\python37\python.exe
cachedir: .pytest_cache
rootdir: E:\Programs\Python\Python_Pytest\TestScripts
plugins: xdist-1.29.0, timeout-1.3.3, repeat-0.8.0, instafail-0.4.1, forked-1.0.2, emoji-0.2.0, allure-pytest-2.6.3
collected 2 items / 1 deselected / 1 selected
test_five.py::test_task_equality FAILED [100%]
============================================= FAILURES =======================================================
_______________________________________ test_task_equality ___________________________________________________
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
> assert t1 == t2
E AssertionError: assert Task(summary=...alse, id=None) == Task(summary='...alse, id=None)
E At index 0 diff: 'sit there' != 'do something'
E Full diff:
E - Task(summary='sit there', owner='brain', done=False, id=None)
E ? ^^^ ^^^ ^^^^
E + Task(summary='do something', owner='okken', done=False, id=None)
E ? +++ ^^^ ^^^ ^^^^
test_five.py:14: AssertionError
--------------------------------------- Captured stdout call ------------------------------------------------
Task(summary='sit there', owner='brain', done=False, id=None)
Task(summary='do something', owner='okken', done=False, id=None)
========================================= warnings summary ===================================================
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.smoke - is this a typo? You can register custom marks to avoi
d this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.dict - is this a typo? You can register custom marks to avoid
this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
-- Docs: https://docs.pytest.org/en/latest/warnings.html
============================= 1 failed, 1 deselected, 2 warnings in 0.14 seconds =============================
跳过测试
from collections import namedtuple
import pytest
Task = namedtuple('Task', ['summary','owner','done','id'])
# __new__.__defaults__创建默认的Task对象
Task.__new__.__defaults__ = (None, None, False, None)
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
assert t1 == t2
@pytest.mark.dict
@pytest.mark.smoke
@pytest.mark.skip(reason="跳过原因你不知道吗？")
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
assert t1_dict == t2_dict
E:\Programs\Python\Python_Pytest\TestScripts>pytest -v test_five.py
======================================= test session starts ==================================================
platform win32 -- Python 3.7.3, pytest-4.5.0, py-1.8.0, pluggy-0.11.0 -- c:\python37\python.exe
cachedir: .pytest_cache
rootdir: E:\Programs\Python\Python_Pytest\TestScripts
plugins: xdist-1.29.0, timeout-1.3.3, repeat-0.8.0, instafail-0.4.1, forked-1.0.2, emoji-0.2.0, allure-pytest-2.6.3
collected 2 items
test_five.py::test_task_equality FAILED [ 50%]
test_five.py::test_dict_equal SKIPPED [100%]
============================================== FAILURES ======================================================
_____________________________________________ test_task_equality _____________________________________________
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
> assert t1 == t2
E AssertionError: assert Task(summary=...alse, id=None) == Task(summary='...alse, id=None)
E At index 0 diff: 'sit there' != 'do something'
E Full diff:
E - Task(summary='sit there', owner='brain', done=False, id=None)
E ? ^^^ ^^^ ^^^^
E + Task(summary='do something', owner='okken', done=False, id=None)
E ? +++ ^^^ ^^^ ^^^^
test_five.py:14: AssertionError
--------------------------------------- Captured stdout call -------------------------------------------------
Task(summary='sit there', owner='brain', done=False, id=None)
Task(summary='do something', owner='okken', done=False, id=None)
========================================= warnings summary ===================================================
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.smoke - is this a typo? You can register custom marks to avoi
d this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.dict - is this a typo? You can register custom marks to avoid
this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
-- Docs: https://docs.pytest.org/en/latest/warnings.html
============================= 1 failed, 1 skipped, 2 warnings in 0.21 seconds ================================
从测试结果中我们看到，测试用例test_five.py::test_dict_equal SKIPPED 被跳过了，然而跳过原因并没有如期的展示出来，可以使用参数-rs来展示跳过原因，如下方式：
E:\Programs\Python\Python_Pytest\TestScripts>pytest -rs test_five.py
==================================== test session starts =====================================================
platform win32 -- Python 3.7.3, pytest-4.5.0, py-1.8.0, pluggy-0.11.0
rootdir: E:\Programs\Python\Python_Pytest\TestScripts
plugins: xdist-1.29.0, timeout-1.3.3, repeat-0.8.0, instafail-0.4.1, forked-1.0.2, emoji-0.2.0, allure-pytest-2.6.3
collected 2 items
test_five.py Fs [100%]
========================================== FAILURES ==========================================================
________________________________________ test_task_equality __________________________________________________
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
> assert t1 == t2
E AssertionError: assert Task(summary=...alse, id=None) == Task(summary='...alse, id=None)
E At index 0 diff: 'sit there' != 'do something'
E Use -v to get the full diff
test_five.py:14: AssertionError
-------------------------------------------- Captured stdout call --------------------------------------------
Task(summary='sit there', owner='brain', done=False, id=None)
Task(summary='do something', owner='okken', done=False, id=None)
============================================== warnings summary ==============================================
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.smoke - is this a typo? You can register custom marks to avoi
d this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
c:\python37\lib\site-packages\_pytest\mark\structures.py:324
c:\python37\lib\site-packages\_pytest\mark\structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.dict - is this a typo? You can register custom marks to avoid
this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
-- Docs: https://docs.pytest.org/en/latest/warnings.html
==================================== short test summary info =================================================
SKIPPED [1] test_five.py:17: 跳过原因你不知道吗？
============================== 1 failed, 1 skipped, 2 warnings in 0.14 seconds ===============================
还可以给跳过添加理由，例如当selenium版本是1.0.4的时候跳过
from collections import namedtuple
import pytest
import selenium
Task = namedtuple('Task', ['summary','owner','done','id'])
# __new__.__defaults__创建默认的Task对象
Task.__new__.__defaults__ = (None, None, False, None)
@pytest.mark.smoke
def test_task_equality():
t1 = Task('sit there', 'brain')
t2 = Task('do something', 'okken')
print(t1)
print(t2)
assert t1 == t2
@pytest.mark.dict
@pytest.mark.smoke
@pytest.mark.skipif(selenium.__version__ == '1.0.4', reason="跳过原因你不知道吗？")
def test_dict_equal():
t1_dict = Task('make sandwich', 'okken')._asdict()
t2_dict = Task('make sandwich', 'okkem')._asdict()
print(t1_dict)
print(t2_dict)
assert t1_dict == t2_dict
运行测试子集
运行单个目录，只需要将目录作为pytest的参数即可
pytest -v test/func --tb=no
运行单个测试函数，只需要在文件名后添加::符号和函数名
pytest -v test/func/test_five.py::test_dict_equal
运行单个测试类，与运行单个测试函数类似,在文件名后添加::符号和类名
pytest -v test/func/test_five.py::Test_Update
运行单个测试类中的测试方法，在文件名后添加::符号和类名然后再跟::符号和函数名
pytest -v test/func/test_five.py::Test_Update::test_dict_equal