在python中用assert_call with進行模擬

Question

我需要確保在python中使用特定參數調用函數。 我已經使用魔術模擬嘲笑了此功能。

self.function = MagicMock()
self.function(subject= "Hello World")

是否存在某些類似的東西

self.function.assert_called_with("Hello World")

要么

self.function.assert_called_with(subject= "Hello World")

抱歉，以前是否有人問過這個問題，但是我一直在嘲笑模擬文檔，而且似乎所有assert語句都不會對我有用。

編輯：我添加了一些調試輸出

當我嘗試調試時，我看到

AssertionError: 
Expected call: mock('Hello World')
Actual call: mock('thing i dont care about', 'Hello World', 'thing i dont care about')

因此，顯然，該函數被調用，但是斷言的行為很奇怪。 它在參數列表或其他內容中無法識別“ Hello World”。

編輯2：

我稍微修改了一下代碼，但仍然無法正確匹配

self.function = MagicMock(field1 = None, field2 = None, subject = None, field4 = None)

#later on...
self.function(1,2,"Hello World",4)  #these params will not always be 1,2,4 .. I made them so to
                                     #show an example

#even further down the road
self.function.assert_called_with(ANY, ANY, "Hello World", ANY)

這樣的事情對我也不起作用。 仍然出現錯誤

AssertionError: 
Expected call: mock(<ANY>, <ANY>, "Hello World", <ANY>)
Actual call: mock(1,2,"Hello World", 4)

再說一次，我不能做類似的事情

“ ANY”如何與匹配參數的模式相對應？

Answer 1

您所寫的內容完全可以按預期工作。 取出自我，這是一個簡化的版本-

func = mock.MagicMock()
func(subject="Hello World")
# assert that func was indeed called with subject="Hello World"
# this goes well since it was indeed called with "Hello World"
func.assert_called_with(subject="Hello World") 
# this fails since func was not called with "Bye World"
AssertionError: Expected call: mock(subject='Bye World')
Actual call: mock(subject='Hello World') 
# The mock also distinguishes between calls with positional and keyword arguments
# so func(subject="Hello World") is not same as func("Hello World") w.r.t.
# the assert statements

那是預期的。 因此，如果您想確保使用預期參數確實調用了模擬函數，只需使用-

func(key=<args>)
func.assert_called_with(key=<args>)

要么

func(<args>)
func.assert_called_with(<args>)

只要記住要在調用和斷言中匹配函數簽名即可。