检查是否使用不同参数多次调用函数

Question

假设我们有一个函数f(x,y)和另一个函数

def g():
       # ...
       f(i,j) # i,j vary and f is called multiple times
       # ...

我们想编写一个单元测试来检查 f 被调用的次数和参数是否正确。

def test_g():
      with patch('mymodule.f') as function:
          assert function.gacs.call_count == correct_no_calls

有

function.assert_called_with(...)

但这只是指最后一次通话。所以假设 g 调用 f(1,2) 然后 f(2,3)，function.assert_called_with(1,2) 是 False.

此外，还有

function.call_args_list

这会生成一个包含 call 个具有正确参数的对象的列表。将此列表与我们在单元测试中创建的 call 对象进行比较感觉是一件非常讨厌的事情。 call 似乎是模拟库的内部 class。

有更好的方法吗？我使用此设置来测试 apply 函数的并行执行。

Answer 1

测试您提供的 Mock().mock_calls list is equal to a list of mock.call() objects 是否：

self.assertEquals(function.mock_calls, [
    mock.call(1, 2),
    mock.call(2, 3),
])

这为您提供了精确的控制，要求调用顺序和调用次数都匹配。

mock.call() class 不是内部的，它旨在用于此类断言。

Answer 2

即使@MartinPieters 的回答是正确的，我认为这不是最好的方法。模拟提供 assert_has_calls 来完成这种职责。

您的测试可能是：

function.assert_has_calls([mock.call(1, 2), mock.call(2, 3)])

其中 mock.call 是帮手 class 从事此类工作。

注意是has调用，表示调用列表应该在调用列表中，不相等。为了解决这个问题，我通常定义自己的助手 assert_is_calls() 如下

def assert_is_calls(m, calls, any_order=False):
   assert len(m.mock_calls) == len(calls)
   m.assert_has_calls(calls, any_order=any_order)

简历范例

>>> import mock
>>> f = mock.Mock()
>>> f(1)
<Mock name='mock()' id='139836302999952'>
>>> f(2)
<Mock name='mock()' id='139836302999952'>
>>> f.assert_has_calls([mock.call(1), mock.call(2)])
>>> f.assert_has_calls([mock.call(2), mock.call(1)])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/damico/.local/lib/python2.7/site-packages/mock/mock.py", line 969, in assert_has_calls
    ), cause)
  File "/home/damico/.local/lib/python2.7/site-packages/six.py", line 718, in raise_from
    raise value
AssertionError: Calls not found.
Expected: [call(2), call(1)]
Actual: [call(1), call(2)]
>>> f.assert_has_calls([mock.call(2), mock.call(1)], any_order=True)
>>> f(3)
<Mock name='mock()' id='139836302999952'>
>>> f.assert_has_calls([mock.call(2), mock.call(1)], any_order=True)
>>> f.assert_has_calls([mock.call(1), mock.call(2)])
>>> assert len(f.mock_calls)==2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError
>>> assert len(f.mock_calls)==3
>>> def assert_is_calls(m, calls, any_order=False):
...    assert len(m.mock_calls) == len(calls)
...    m.assert_has_calls(calls, any_order=any_order)
... 
>>> assert_is_calls(f, [mock.call(1), mock.call(2), mock.call(3)])
>>> assert_is_calls(f, [mock.call(1), mock.call(3), mock.call(2)])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in assert_is_calls
  File "/home/damico/.local/lib/python2.7/site-packages/mock/mock.py", line 969, in assert_has_calls
    ), cause)
  File "/home/damico/.local/lib/python2.7/site-packages/six.py", line 718, in raise_from
    raise value
AssertionError: Calls not found.
Expected: [call(1), call(3), call(2)]
Actual: [call(1), call(2), call(3)]
>>> assert_is_calls(f, [mock.call(1), mock.call(3), mock.call(2)], True)
>>> assert_is_calls(f, [mock.call(1), mock.call(3)], True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in assert_is_calls
AssertionError
>>>

检查是否使用不同参数多次调用函数

Checking whether function has been called multiple times with different parameters

python

testing

unit-testing

mocking