如何通过测试正确设置和拆除我的pytest类？

Question

我正在使用selenium进行端到端测试,我无法获得如何使用setup_class和teardown_class方法.

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.

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是用于类,而是用于对象.我self在每个测试方法中传递param,所以我可以访问对象的变量:

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..它应该分别为每个对象创建,对吧？

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

Answer 1

根据Fixture定型/执行拆解代码的使用addfinalizer是"历史".

作为历史记录,另一种编写拆卸代码的方法是将一个请求对象接受到fixture函数中,并可以调用其request.addfinalizer一次或多次:

目前安装和拆卸的最佳实践是使用 yield

import pytest

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

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

运行它会导致

$ 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 ===

Answer 2

当你编写"定义为类方法的测试"时,你真的是指类方法(接收其类作为第一个参数的方法)还是常规方法(接收实例作为第一个参数的方法)？

由于您的示例self用于测试方法,我假设后者,所以您只需要使用setup_method:

class Test:

    def setup_method(self, test_method):
        # configure self.attribute

    def teardown_method(self, test_method):
        # tear down self.attribute

    def test_buttons(self):
        # use self.attribute for test

测试方法实例传递给setup_method和teardown_method,但如果您的setup/teardown代码不需要知道测试上下文,则可以忽略.更多信息可以在这里找到.

我还建议你熟悉py.test的灯具,因为它们是一个更强大的概念.

Answer 3

正如@Bruno建议的那样,使用pytest fixture是另一种解决方案,可以访问两个测试类甚至只是简单的测试函数.这是一个测试python2.7函数的例子:

import pytest

@pytest.fixture(scope='function')
def some_resource(request):
    stuff_i_setup = ["I setup"]

    def some_teardown():
        stuff_i_setup[0] += " ... but now I'm torn down..."
        print stuff_i_setup[0]
    request.addfinalizer(some_teardown)

    return stuff_i_setup[0]

def test_1_that_needs_resource(some_resource):
    print some_resource + "... and now I'm testing things..."

所以,跑步test_1...产生:

I setup... and now I'm testing things...
I setup ... but now I'm torn down...

请注意,stuff_i_setup在fixture中引用了该对象,setup并允许该对象进行torn down与之交互的测试.您可以想象这对于持久对象(例如假设数据库或某些连接)非常有用,必须在每次测试运行之前将其清除以保持隔离.

Answer 4

这可能有助于http://docs.pytest.org/en/latest/xunit_setup.html

在我的测试套件中,我将测试用例分组到类中.对于我需要该类中所有测试用例的设置和拆解,我使用了setup_class(cls)和teardown_class(cls)classmethods.

对于每个测试用例我需要的设置和拆卸,我使用setup_method(method)和teardown_method(methods)

例:

lh = <got log handler from logger module>

class TestClass:
    @classmethod
    def setup_class(cls):
        lh.info("starting class: {} execution".format(cls.__name__))

    @classmethod
    def teardown_class(cls):
        lh.info("starting class: {} execution".format(cls.__name__))

    def setup_method(self, method):
        lh.info("starting execution of tc: {}".format(method.__name__))

    def teardown_method(self, method):
        lh.info("starting execution of tc: {}".format(method.__name__))

    def test_tc1(self):
        <tc_content>
        assert 

    def test_tc2(self):
        <tc_content>
        assert

现在,当我运行我的测试时,当TestClass执行开始时,它会记录它何时开始执行,何时结束执行以及方法相同的详细信息.

您可以在相应位置添加其他设置和拆卸步骤.

希望能帮助到你!

Answer 5

如果添加@classmethod装饰器,您的代码应该像您期望的那样工作.

@classmethod 
def setup_class(cls):
    "Runs once per class"

@classmethod 
def teardown_class(cls):
    "Runs at end of class"

见http://pythontesting.net/framework/pytest/pytest-xunit-style-fixtures/

Answer 6

如果你像我一样，想要一次性获得所有可能变化的快速食谱以供以后使用或只是复习一下，这里就有了。

所以，有 2主要的方式来设置/拆卸测试（不包括unittest集成，即当你实际使用unittest时）

1）Fixture（pytest方式）

2）xunit-style（类似于unittest）

这些食谱可以在我的Programming-CookBook中找到-> PyTest Recipes

夹具

夹具设置/拆卸的集合

• 食谱

import pytest

counter = 0

def add_counter():
    global counter
    counter += 1

# ---------------------------
# yield fixtures (recommended)
# ---------------------------


@pytest.fixture
def get_counter():
    print(f"{counter}) -- Fixture (yield)")
    add_counter()
    yield counter


def test_count_is_1(get_counter):
    assert get_counter == 1

def test_count_is_2(get_counter):
    assert get_counter == 2

# ---------------------------
# Adding finalizers directly
# ---------------------------

@pytest.fixture
def get_counter_direct(request):
    print(f"{counter}) -- Fixture (request)")
    add_counter()

    request.addfinalizer(add_counter)
    return counter

def test_count_is_3(get_counter_direct):
    assert get_counter_direct == 3

这导致

================================================================================================================ PASSES ================================================================================================================
___________________________________________________________________________________________________________ test_count_is_1 ____________________________________________________________________________________________________________
-------------------------------------------------------------------------------------------------------- Captured stdout setup ---------------------------------------------------------------------------------------------------------
0) -- Fixture (yield)
___________________________________________________________________________________________________________ test_count_is_2 ____________________________________________________________________________________________________________
-------------------------------------------------------------------------------------------------------- Captured stdout setup ---------------------------------------------------------------------------------------------------------
1) -- Fixture (yield)
___________________________________________________________________________________________________________ test_count_is_3 ____________________________________________________________________________________________________________
-------------------------------------------------------------------------------------------------------- Captured stdout setup ---------------------------------------------------------------------------------------------------------
2) -- Fixture (request)
========================================================================================================== 3 passed in 0.01s ==========================================================================================================

xunit风格

这些都是xunit风格的setup/teardown方式的集合。这里我添加了一个计数器，以便订单可见

• 食谱

import pytest

counter = 0

def add_counter():
    global counter
    counter += 1

# ---------------------------
# Module Level Setup/TearDown
# ---------------------------
def setup_module(module):
    """setup any state specific to the execution of the given module."""
    add_counter()
    print(f"{counter}) -- SetUp (module)")

def teardown_module(module):
    """teardown any state that was previously setup with a setup_module method."""
    add_counter()
    print(f"{counter}) -- tearDown (module)")

class TestSomeClass:

    # ---------------------------
    # Class level setup/teardown
    # ---------------------------
    @classmethod
    def setup_class(cls):
        """setup any state specific to the execution of the given class (which usually contains tests)."""
        add_counter()
        print(f"{counter}) -- SetUp (class)")

    @classmethod
    def teardown_class(cls):
        """teardown any state that was previously setup with a call to setup_class. """
        add_counter()
        print(f"{counter}) -- tearDown (class)")

    # ---------------------------
    # Class level setup/teardown
    # ---------------------------
    def setup_method(self, method):
        """setup any state tied to the execution of the given method in a class.  setup_method is invoked for every test method of a class."""
        add_counter()
        print(f"{counter}) -- SetUp (method)")

    def teardown_method(self, method):
        """teardown any state that was previously setup with a setup_method call. """
        add_counter()
        print(f"{counter}) -- tearDown (method)")

    def test_is_1_a_number(self):
        assert (1).__class__ is int


# ---------------------------
# module level  setup/teardown
# ---------------------------
def setup_function(function):
    """setup any state tied to the execution of the given function. Invoked for every test function in the module."""
    add_counter()
    print(f"{counter}) -- SetUp (function)")


def teardown_function(function):
    """teardown any state that was previously setup with a setup_function call."""
    add_counter()
    print(f"{counter}) -- tearDown (function)")

def test_something_at_module_level():
    assert (1).__class__ is int

这导致

================================================================================================================ PASSES ================================================================================================================
___________________________________________________________________________________________________ TestSomeClass.test_is_1_a_number ___________________________________________________________________________________________________
-------------------------------------------------------------------------------------------------------- Captured stdout setup ---------------------------------------------------------------------------------------------------------
1) -- SetUp (module)
2) -- SetUp (class)
3) -- SetUp (method)
------------------------------------------------------------------------------------------------------- Captured stdout teardown -------------------------------------------------------------------------------------------------------
4) -- tearDown (method)
5) -- tearDown (class)
____________________________________________________________________________________________________ test_something_at_module_level ____________________________________________________________________________________________________
-------------------------------------------------------------------------------------------------------- Captured stdout setup ---------------------------------------------------------------------------------------------------------
6) -- SetUp (function)
------------------------------------------------------------------------------------------------------- Captured stdout teardown -------------------------------------------------------------------------------------------------------
7) -- tearDown (function)
8) -- tearDown (module)
========================================================================================================== 2 passed in 0.01s ===========================================================================================================

文档

• 拆卸/清理（又称夹具最终确定）
• 如何实现 xunit 风格的设置
• 关于赛程

Answer 7

import pytest
class Test:
    @pytest.fixture()
    def setUp(self):
        print("setup")
        yield "resource"
        print("teardown")

    def test_that_depends_on_resource(self, setUp):
        print("testing {}".format(setUp))

为了运行：

pytest nam_of_the_module.py -v