斷言派生類方法的調用順序正確

Question

我正在嘗試驗證Base.run_this的實現是否以正確的順序調用了派生類的方法（derived_method_ [1st | 2nd | 3rd]）。 如輸出所示，該測試無法正常工作。 我怎樣才能解決這個問題？

class Base(object):
  __metaclass__ = abc.ABCMeta

  def __init__(self, parameters):
   self.parameters = parameters;

  @abc.abstractmethod
  def must_implement_this(self):
   return

  def run_this(self):
   self.must_implement_this()
   if(self.parameters):
    first = getattr(self, "derived_method_1st")
    first()
    second = getattr(self, "derived_method_2nd")
    second()
    third = getattr(self, "derived_method_3rd")
    third()

class Derived(Base):
  def must_implement_this(self):
   pass
  def derived_method_1st(self):
   pass
  def derived_method_2nd(self):
   pass
  def derived_method_3rd(self):
   pass

mocked = MagicMock(wraps=Derived(True))
mocked.run_this()
mocked.assert_has_calls([call.derived_method_1st(), call.derived_method_2nd(), call.derived_method_3rd()])

輸出量

AssertionError: Calls not found.
  Expected: [call.derived_method_1st(), call.derived_method_2nd(),   call.derived_method_3rd()]
  Actual: [call.run_this()]

Answer 1

wraps不適用於實例 。 此處發生的是mocked.run_this返回一個新的模擬對象，該對象“包裝”了Derived(True).run_this ，后者是原始 Derived()實例的綁定方法。

這樣，該方法將調用綁定到該原始實例（而不是模擬對象）的self.derived_method_*方法。

您可以run_this在spec模擬中修補run_this方法：

mock = MagicMock(spec=Derived)
instance = mock()
instance.run_this = Derived.run_this.__get__(instance)  # bind to mock instead
instance.parameters = True  # adjust as needed for the test
instance.run_this()

演示：

>>> mock = MagicMock(spec=Derived)
>>> instance = mock()
>>> instance.run_this = Derived.run_this.__get__(instance)  # bind to mock instead
>>> instance.parameters = True  # adjust as needed for the test
>>> instance.run_this()
>>> instance.mock_calls
[call.must_implement_this(),
 call.derived_method_1st(),
 call.derived_method_2nd(),
 call.derived_method_3rd()]