pytest
安装与入门
1.pip install -U pytest
2.创建一个test01.py的文件
def func(x):
return x + 1
def test_answer():
assert func(3) == 5
3.在该目录下执行pytest(venv)
D:\4_code\study>pytest
============================= test session starts =============================
platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1
rootdir: D:\4_code\study, inifile:
collected 1 item
test01.py . [100%]
========================== 1 passed in 0.19 seconds ===========================
(venv) D:\4_code\study>pytest
4.执行多个，新建一个py文件 test02.py
def add(x, y):
return x + y
def test_add():
assert add(1, 0) == 1
assert add(1, 1) == 2
assert add(1, 99) == 100
执行pytest
(venv) D:\4_code\study>pytest
============================= test session starts =============================
platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1
rootdir: D:\4_code\study, inifile:
collected 2 items
test01.py . [ 50%]
test02.py . [100%]
========================== 2 passed in 0.30 seconds ===========================
pytest将在当前目录及其子目录中运行test _ * .py或* _test.py形式的所有文件。
5.在一个类中组合多个测试
一旦开发了多个测试，您可能希望将它们分组到一个类中。pytest可以很容易地创建一个包含多个测试的类：
class TestClass(object):
def test_one(self):
x = "this"
assert 'h' in x
def test_two(self):
x = "hello"
assert hasattr(x, 'check')
(venv) D:\4_code\study>pytest
============================= test session starts =============================
platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1
rootdir: D:\4_code\study, inifile:
collected 4 items
test_calc.py . [ 25%]
test_class.py .F [ 75%]
test_quick_start.py . [100%]
================================== FAILURES ===================================
_____________________________ TestClass.test_two ______________________________
self = <test_class.TestClass object at 0x058A59F0>
def test_two(self):
x = "hello"
test_class.py:16: AssertionError
===================== 1 failed, 3 passed in 0.37 seconds ======================
6.指定测试 用例
(venv) D:\4_code\study>pytest -q test_calc.py
. [100%]
1 passed in 0.02 seconds
7.Assert
pytest使用的是python自带的assert关键字来进行断言
assert关键字后面可以接一个表达式，只要表达式的最终结果为True，那么断言通过，用例执行成功，否则用例执行失败
断言异常抛出
如
import pytest
def test_zero_division():
with pytest.raises(ZeroDivisionError):
1 / 0
1/0的时候应该抛出ZeroDivisionError，否则用例失败，断言不通过。
8.Fixture
如测试数据为
[
{"name":"jack","password":"Iloverose"},
{"name":"rose","password":"Ilovejack"},
{"name":"tom","password":"password123"}
]
import pytest
import json
class TestUserPassword(object):
@pytest.fixture
def users(self):
return json.loads(open('./users.dev.json', 'r').read()) # 读取当前路径下的users.dev.json文件，返回的结果是dict
def test_user_password(self, users):
# 遍历每条user数据
for user in users:
passwd = user['password']
assert len(passwd) >= 6
msg = "user %s has a weak password" %(user['name'])
assert passwd != 'password', msg
assert passwd != 'password123', msg
(venv) D:\4_code\study>pytest test_user_password.py
============================= test session starts =============================
platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1
rootdir: D:\4_code\study, inifile:
collected 1 item
test_user_password.py F [100%]
================================== FAILURES ===================================
_____________________ TestUserPassword.test_user_password _____________________
self = <test_user_password.TestUserPassword object at 0x044783B0>
users = [{'name': 'jack', 'password': 'Iloverose'}, {'name': 'rose', 'password': 'Ilovejack'}, {'name': 'tom', 'password': 'password123'}]
def test_user_password(self, users):
# 遍历每条user数据
for user in users:
passwd = user['password']
assert len(passwd) >= 6
msg = "user %s has a weak password" %(user['name'])
assert passwd != 'password', msg
> assert passwd != 'password123', msg
E AssertionError: user tom has a weak password
E assert 'password123' != 'password123'
test_user_password.py:16: AssertionError
========================== 1 failed in 0.26 seconds ===========================
使用@pytest.fixture装饰器可以定义feature
在用例的参数中传递fixture的名称以便直接调用fixture，拿到fixture的返回值
3个assert是递进关系，前1个assert断言失败后，后面的assert是不会运行的，因此重要的assert放到前面
E AssertionError: user tom has a weak password可以很容易的判断出是哪条数据出了问题，所以定制可读性好的错误信息是很必要的
任何1个断言失败以后，for循环就会退出，所以上面的用例1次只能发现1条错误数据，换句话说任何1个assert失败后，用例就终止运行了
执行顺序
pytest找到以test_开头的方法，也就是test_user_password方法，执行该方法时发现传入的参数里有跟fixture users名称相同的参数
pytest认定users是fixture，执行该fixture，读取json文件解析成dict实例
test_user_password方法真正被执行，users fixture被传入到该方法
使用下面的命令来查看用例中可用的fixtures
pytest --fixtures test_user_password.py
------------------ fixtures defined from test_user_password -------------------
users
test_user_password.py:6: no docstring available
======================== no tests ran in 0.07 seconds =========================
数据清理
有时候我们需要在用例结束的时候去清理一些测试数据，或清除测试过程中创建的对象，我们可以使用下面的方式
import smtplib
import pytest
@pytest.fixture(scope="module")
def smtp():
smtp = smtplib.SMTP("smtp.gmail.com", 587, timeout=5)
yield smtp # provide the fixture value
print("teardown smtp")
smtp.close()
yield 关键字返回了fixture中实例化的对象smtp
module中的用例执行完成后smtp.close()方法会执行，无论用例的运行状态是怎么样的,都会执行