Using Matchers.any() to match a mock object

Foo mockFoo1 = mock(Foo.class);
Foo mockFoo2 = mock(Foo.class);
when(((Foo) any()).someMethod()).thenReturn("Hello");

In the above sample code, line 3 fails with a NullPointerException. Why so?

开发者_Python百科

My thought on this:

EITHER.. any() should be used for matching parameters rather than matching the objects on which methods are triggered.

OR .. any() works only for real concrete objects and not mock objects.

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You need to do:

Foo mockFoo1 = mock(Foo.class);
Foo mockFoo2 = mock(Foo.class);
when(mockFoo1).someMethod().thenReturn("Hello");
when(mockFoo2).someMethod().thenReturn("Hello");

any() (shorter alias to anyObject()) is an Mockito argument matcher that matches any argument and only should be used as follows:

when(mockFoo1.someMethod(any())).thenReturn("Hello");

any() returns null, so your code was equivalent to

when(((Foo) null).someMethod()).thenReturn("Hello");