如何使用测试正确设置和拆卸我的 pytest 类? [英] How do I correctly setup and teardown for my pytest class with tests?

问题描述

我使用 selenium 进行端到端测试，但我不知道如何使用 setup_class 和 teardown_class 方法.

I am using selenium for end to end testing and I can't get how to use setup_class and teardown_class methods.

我需要在setup_class 方法中设置浏览器，然后执行一系列定义为类方法的测试，最后在teardown_class 方法中退出浏览器.

I need to set up browser in setup_class method, then perform a bunch of tests defined as class methods and finally quit browser in teardown_class method.

但从逻辑上讲，这似乎是一个糟糕的解决方案，因为实际上我的测试不适用于类，但适用于对象.我在每个测试方法中传递 self 参数，所以我可以访问对象的变量:

But logically it seems like a bad solution, because in fact my tests will not work with class, but with object. I pass self param inside every test method, so I can access objects' vars:

class TestClass:
  
    def setup_class(cls):
        pass
        
    def test_buttons(self, data):
        # self.$attribute can be used, but not cls.$attribute?  
        pass
        
    def test_buttons2(self, data):
        # self.$attribute can be used, but not cls.$attribute?
        pass
        
    def teardown_class(cls):
        pass
    

甚至为类创建浏览器实例似乎也不正确..它应该为每个对象单独创建，对吗?

And it even seems not to be correct to create browser instance for class.. It should be created for every object separately, right?

所以，我需要使用 __init__ 和 __del__ 方法而不是 setup_class 和 teardown_class 吗?

So, I need to use __init__ and __del__ methods instead of setup_class and teardown_class?

推荐答案

根据 Fixture 终结/执行拆卸代码，目前设置和拆卸的最佳实践是使用 yield 而不是 return:

According to Fixture finalization / executing teardown code, the current best practice for setup and teardown is to use yield instead of return:

import pytest

@pytest.fixture()
def resource():
    print("setup")
    yield "resource"
    print("teardown")

class TestResource:
    def test_that_depends_on_resource(self, resource):
        print("testing {}".format(resource))

运行结果

$ py.test --capture=no pytest_yield.py
=== test session starts ===
platform darwin -- Python 2.7.10, pytest-3.0.2, py-1.4.31, pluggy-0.3.1
collected 1 items

pytest_yield.py setup
testing resource
.teardown


=== 1 passed in 0.01 seconds ===

另一种编写拆卸代码的方法是接受一个请求-context object 进入你的夹具函数，并使用一个执行一次或多次拆卸的函数调用它的 request.addfinalizer 方法:

Another way to write teardown code is by accepting a request-context object into your fixture function and calling its request.addfinalizer method with a function that performs the teardown one or multiple times:

import pytest

@pytest.fixture()
def resource(request):
    print("setup")

    def teardown():
        print("teardown")
    request.addfinalizer(teardown)
    
    return "resource"

class TestResource:
    def test_that_depends_on_resource(self, resource):
        print("testing {}".format(resource))

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