引入
我们之前学习的都是测试用例的前置固件，也就是相当于“setup”。说到这，细心的你可能想到了，那有没有什么方式可以表示出“teardown”？这就是我们今天学习的yield和addfinalizer。
yield
yield是一个关键字，它不是单独存在的，要写在fixtrue标记的固件中。
我们在声明的固件myfixture中加入yield关键字，在它下面写测试用例执行后想要运行的代码；其他有关于固件的使用没有任何差别。需要说明的一点是我们在pytest主函数中增加了一个参数“–setup-show”，他会显示出固件的执行情况。
import pytest@pytest.fixture()
def myfixture():print("执行myfixture前半部分")yieldprint("执行myfixture的后半部分")class Test_firstFile():def test_one(self,myfixture):print("执行test_one")assert 1+2==3def test_two(self):print("执行test_two")assert 1==1def test_three(self):print("执行test_three")assert 1+1==2if __name__=="__main__":pytest.main(["--setup-show","-s","test03.py"])"C:\Program Files\Python35\python.exe" C:/Users/wangli/PycharmProjects/Test/test/test03.py
============================= test session starts =============================
platform win32 -- Python 3.5.2, pytest-5.1.2, py-1.8.0, pluggy-0.12.0
rootdir: C:\Users\wangli\PycharmProjects\Test\test
collected 3 itemstest03.py 执行myfixture前半部分SETUP F myfixturetest03.py::Test_firstFile::test_one (fixtures used: myfixture)执行test_one
.执行myfixture的后半部分TEARDOWN F myfixturetest03.py::Test_firstFile::test_two执行test_two
.test03.py::Test_firstFile::test_three执行test_three
.============================== 3 passed in 0.03s ==============================Process finished with exit code 0fixture里面的teardown用yield来唤醒teardown的执行
@pytest.fixture(scope="function",autouse=True)
def open():print("打开浏览器，并且打开百度首页")yieldprint("执行teardown!")def test_s1(open):print("用例1：搜索python-1",open)def test_s2():print("用例2：搜索python-2")def test_s3():print("用例3：搜索python-3")if __name__=="__main__":pytest.main(["--setup-show","-s","test03.py"])"C:\Program Files\Python35\python.exe" C:/Users/wangli/PycharmProjects/Test/test/test03.py
============================= test session starts =============================
platform win32 -- Python 3.5.2, pytest-5.1.2, py-1.8.0, pluggy-0.12.0
rootdir: C:\Users\wangli\PycharmProjects\Test\test
collected 3 itemstest03.py 打开浏览器，并且打开百度首页SETUP F opentest03.py::test_s1 (fixtures used: open)用例1：搜索python-1 None
.执行teardown!TEARDOWN F open打开浏览器，并且打开百度首页SETUP F opentest03.py::test_s2 (fixtures used: open)用例2：搜索python-2
.执行teardown!TEARDOWN F open打开浏览器，并且打开百度首页SETUP F opentest03.py::test_s3 (fixtures used: open)用例3：搜索python-3
.执行teardown!TEARDOWN F open============================== 3 passed in 0.03s ==============================Process finished with exit code 0如果测试用例中的代码出现异常或者断言失败，并不会影响他的固件中yield后的代码执行；但是如果固件中的yield之前的代码也就是相当于setup部分的带代码，出现错误或断言失败，那么yield后的代码将不会再执行，当然测试用例中的代码也不会执行。
@pytest.fixture(scope="function",autouse=True)
def open():print("打开浏览器，并且打开百度首页")yieldprint("执行teardown!")def test_s1(open):print("用例1：搜索python-1",aaaa)def test_s2():print("用例2：搜索python-2")def test_s3():print("用例3：搜索python-3")if __name__=="__main__":pytest.main(["--setup-show","-s","test03.py"])"C:\Program Files\Python35\python.exe" C:/Users/wangli/PycharmProjects/Test/test/test03.py
============================= test session starts =============================
platform win32 -- Python 3.5.2, pytest-5.1.2, py-1.8.0, pluggy-0.12.0
rootdir: C:\Users\wangli\PycharmProjects\Test\test
collected 3 itemstest03.py 打开浏览器，并且打开百度首页SETUP F opentest03.py::test_s1 (fixtures used: open)F执行teardown!TEARDOWN F open打开浏览器，并且打开百度首页SETUP F opentest03.py::test_s2 (fixtures used: open)用例2：搜索python-2
.执行teardown!TEARDOWN F open打开浏览器，并且打开百度首页SETUP F opentest03.py::test_s3 (fixtures used: open)用例3：搜索python-3
.执行teardown!TEARDOWN F open================================== FAILURES ===================================
___________________________________ test_s1 ___________________________________open = Nonedef test_s1(open):
> print("用例1：搜索python-1",aaaa)
E NameError: name 'aaaa' is not definedtest03.py:78: NameError
========================= 1 failed, 2 passed in 0.13s =========================我们也可以通过request.addfinalizer()的方式实现“teardown”
我们在固件中传入request参数；又在固件中定义了一个内置函数；最后将定义的内置函数添加到request的addfinalizer中。
@pytest.fixture()
def myfixture(request):print ("执行固件myfixture的前半部分")def myteardown():print("执行固件myfture的后半部分")request.addfinalizer(myteardown)class Test_Pytest():def test_one(self,myfixture):print("test_one方法执行" )assert 1==1def test_two(self):print("test_two方法执行" )assert "o" in "love"def test_three(self):print("test_three方法执行" )assert 3-2==1if __name__=="__main__":pytest.main(["--setup-show","-s","test03.py"])"C:\Program Files\Python35\python.exe" C:/Users/wangli/PycharmProjects/Test/test/test03.py
============================= test session starts =============================
platform win32 -- Python 3.5.2, pytest-5.1.2, py-1.8.0, pluggy-0.12.0
rootdir: C:\Users\wangli\PycharmProjects\Test\test
collected 3 itemstest03.py 执行固件myfixture的前半部分SETUP F myfixturetest03.py::Test_Pytest::test_one (fixtures used: myfixture)test_one方法执行
.执行固件myfture的后半部分TEARDOWN F myfixturetest03.py::Test_Pytest::test_twotest_two方法执行
.test03.py::Test_Pytest::test_threetest_three方法执行
.============================== 3 passed in 0.04s ==============================Process finished with exit code 0
