python 中 super() 的单元测试用例

Question

我有一个 class 作为：

"""A"""

from clay import config
from datetime import timedelta
from <path> import B

EXECUTION_TIMEOUT = timedelta(minutes=30)

class A(B):
    """Crawler task for A"""

    def __init__(self, *args, **kwargs):
        """Initialization."""
        super(A, self).__init__(execution_timeout=EXECUTION_TIMEOUT, *args, **kwargs)

我有一个测试文件：

"""Test class for A"""
from datetime import timedelta, datetime
from doubles import allow
from mock import patch, MagicMock
from unittest import TestCase
import mock

from <path> import A


class JobInfoHandler:
    """Mock job info."""

    def __init__(self):
        """Init Method."""
        self.crawlerConfig = None
        pass


class TestA(TestCase):
    """Test class for A."""

    def setUp(self):
        """Create instance of class to test."""
        job_info_ob = JobInfoHandler()
        self.obj_a = A(owner='arahej', task_id='12',
                                              schedule_interval=timedelta(minutes=60), job_info=job_info_ob)

当我运行我的测试覆盖率命令。下面一行不包括在内：

super(A, self).__init__(execution_timeout=EXECUTION_TIMEOUT, *args, **kwargs)

任何人都可以帮助我如何覆盖 super 这里。我尝试模拟或修补，但没有用。

Answer 1

尝试修补超级：

from mock import patch


class B(object):

    def foo(self):
        print('foo from B')


class A(B):

    def foo(self):
        self.called_foo = True
        super(A, self).foo()


class TestA(object):

    @patch('%s.super' % __name__, create=True)
    def test_foo(self, super_func):
        A = A()
        A.foo()
        assert A.called_foo
        assert super_func.called

Answer 2

setUp()方法只在你写一个测试方法时调用documented:

setUp()

Method called to prepare the test fixture. This is called immediately before calling the test method;...

class TestA(TestCase):
    """Test class for A."""

    def setUp(self):
        """Create instance of class to test."""
        print("Setting up testcase")
        job_info_ob = JobInfoHandler()
        self.obj_a = A(owner='arahej', task_id='12',
                                              schedule_interval=timedelta(minutes=60), job_info=job_info_ob)

这里，你还没有定义任何测试方法，因此 setUp() 永远不会被调用，因此 A 永远不会被初始化，这反过来也永远不会调用父 [=18] 的初始化=] 通过 super().__init__().

$ coverage run -m unittest discover

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK
$ coverage html

添加测试方法现在运行 setUp() 将初始化 A.__init__()，然后运行s B.__init__() 通过 super()。

class TestA(TestCase):
    def setUp(self):
        ...

    def test_first(self):
        print("1st test method called")
        assert True

$ coverage run -m unittest discover
Setting up testcase
1st test method called
.
----------------------------------------------------------------------
Ran 1 test in 0.000s

OK
$ coverage html

此外，您提到了 mocks/patches。您可能误解了 mocks/patches 的用途，因为如果您 mock/patch 使用存根实现调用 super().__init__()，那么它不会调用实际实现，而是调用 mocked/patched/stubbed版本，这意味着它不会解决您的问题，因为当您用修补的调用替换实际调用时，您的实际实现的覆盖范围仍然会丢失。换句话说，你只是通过修补让你的问题变得更糟:)

python 中 super() 的单元测试用例

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