如何使用pythons unittest从多个基础测试类继承？

Question

我正在编写一些测试，并希望在不同的 TestCase 类之间共享 setUp 和 tearDown 方法。为此，我认为您可以使用仅实现 setUp 和 tearDown 方法并从中继承的基本测试类。但是，我也有想使用来自多个 setUp 的变量的情况。这是一个例子：

class Base(unittest.TestCase):
    def setUp(self):
        self.shared = 'I am shared between everyone'

    def tearDown(self):
        del self.shared


class Base2(unittest.TestCase):
    def setUp(self):
        self.partial_shared = 'I am shared between only some tests'

    def tearDown(self):
        del self.partial_shared


class Test1(Base):

    def test(self):
        print self.shared
        test_var = 'I only need Base'
        print test_var



class Test2(Base2):

    def test(self):
        print self.partial_shared
        test_var = 'I only need Base2'


class Test3(Base, Base2):

    def test(self):
        test_var = 'I need both Base and Base2'
        print self.shared
        print self.partial_shared


if __name__=='__main__':
    unittest.main()

这是输出：

..EI am shared between everyone
I only need Base
I am shared between only some tests
I am shared between everyone

======================================================================
ERROR: test (__main__.Test3)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/b3053674/Documents/PyCoTools/PyCoTools/Tests/base_tests.py", line 134, in test
    print self.partial_shared
AttributeError: 'Test3' object has no attribute 'partial_shared'

----------------------------------------------------------------------
Ran 3 tests in 0.004s

FAILED (errors=1)

是否可以实现这样的类继承？

Answer 1

Python 支持链式继承。

你可以让class Base2()继承自Base，然后添加你想要的东西。

像这样：

class Base2(Base):
    def setUp(self):
        super(Base2, self).setUp()
        self.partial_shared = 'I am shared between only some tests'

然后从它继承：

class Test3(Base2):

    def test(self):
        test_var = 'I need both Base and Base2'
        print self.shared
        print self.partial_shared