Python的多重继承问题

因为要写个测试用例，测试4层LB，7层LB，这种测试只有一个参数不一样，实在不愿意把代码复制一份，想到了先写一个测试类，在分别继承这个测试类，写俩L4，L7子类
代码如下

class LbTest():
  ##初始化工作
  def setUp(self):
    print "in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)

  #退出清理工作
  def tearDown(self):
    print "in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)

  #具体的测试用例，一定要以test开头
  def testsum(self):
    print "in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)

  def testsub(self):
    print "in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)


class L4LbTestCase(unittest.TestCase, LbTest):
  def __init__(self, methodName='runTest'):
    unittest.TestCase.__init__(self, methodName)
    print ">>> Generate class %s, func %s\n" % (self.__class__.__name__, sys._getframe().f_code.co_name)

  def setUp(self):
    print ">in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)
    LbTest.setUp(self)

  def tearDown(self):
    LbTest.tearDown(self)
    print "<in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)

class L7LbTestCase(unittest.TestCase, LbTest):
  def __init__(self, methodName='runTest'):
    unittest.TestCase.__init__(self, methodName)
    print ">>> Generate class %s, func %s\n" % (self.__class__.__name__, sys._getframe().f_code.co_name)

  def setUp(self):
    print ">in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)
    LbTest.setUp(self)

  def tearDown(self):
    LbTest.tearDown(self)
    print "<in class %s, func %s" % (self.__class__.__name__, sys._getframe().f_code.co_name)

但是执行结果很奇怪

Launching unittests with arguments python -m unittest discover -s D:/code/ -p test_lb.py -t D:\code in D:\code

>>> Generate class L4LbTestCase, func __init__

>>> Generate class L4LbTestCase, func __init__

>>> Generate class L7LbTestCase, func __init__   // 这一块调用不正常，为什么会调用两次？

>>> Generate class L7LbTestCase, func __init__   // 这一块调用不正常
>in class L4LbTestCase, func setUp
in class L4LbTestCase, func setUp
in class L4LbTestCase, func testsub
in class L4LbTestCase, func tearDown
<in class L4LbTestCase, func tearDown
>in class L4LbTestCase, func setUp
in class L4LbTestCase, func setUp
in class L4LbTestCase, func testsum
in class L4LbTestCase, func tearDown
<in class L4LbTestCase, func tearDown
>in class L7LbTestCase, func setUp
in class L7LbTestCase, func setUp
in class L7LbTestCase, func testsub
in class L7LbTestCase, func tearDown
<in class L7LbTestCase, func tearDown
>in class L7LbTestCase, func setUp
in class L7LbTestCase, func setUp
in class L7LbTestCase, func testsum
in class L7LbTestCase, func tearDown
<in class L7LbTestCase, func tearDown


Ran 4 tests in 0.004s

OK

Process finished with exit code 0

另外一段代码

class A(object):
    def __init__(self):
        print 'Running A.__init__'
        super(A, self).__init__()
        print 'Leaving A.__init__'


class B(A):
    def __init__(self):
        print 'Running B.__init__ '
        super(B,self).__init__()
        #A.__init__(self)
        print 'Leaving B.__init__ '


class C(A):
    def __init__(self):
        print 'Running C.__init__ '
        super(C, self).__init__()
        print 'Leaving C__init__ '

class D(A):
    def __init__(self):
        print 'Running D.__init__ '
        super(D, self).__init__()
        print 'Leaving D.__init__ '

class E(B, C,D):
    def __init__(self):
        print 'Running E.__init__ '
        super(E, self).__init__()
        print 'Leaving E.__init__ '


foo = E()

执行结果

Leaving A.__init__
Leaving B.__init__ 
Leaving C__init__ 
Leaving D.__init__ 
Leaving E.__init__ 
Running E.__init__ 
Running B.__init__ 
Running C.__init__ 
Running D.__init__ 
Running A.__init__