How to use ArgumentCaptor for stubbing?

Hypothetically, if search landed you on this question then you probably want this:

doReturn(someReturn).when(someObject).doSomething(argThat(argument -> argument.getName().equals("Bob")));

Why? Because like me you value time and you are not going to implement .equals just for the sake of the single test scenario.

And 99 % of tests fall apart with null returned from Mock and in a reasonable design you would avoid return null at all costs, use Optional or move to Kotlin. This implies that verify does not need to be used that often and ArgumentCaptors are just too tedious to write.

Assuming the following method to test:

public boolean doSomething(SomeClass arg);

Mockito documentation says that you should not use captor in this way:

when(someObject.doSomething(argumentCaptor.capture())).thenReturn(true);
assertThat(argumentCaptor.getValue(), equalTo(expected));

Because you can just use matcher during stubbing:

when(someObject.doSomething(eq(expected))).thenReturn(true);

But verification is a different story. If your test needs to ensure that this method was called with a specific argument, use ArgumentCaptor and this is the case for which it is designed:

ArgumentCaptor<SomeClass> argumentCaptor = ArgumentCaptor.forClass(SomeClass.class);
verify(someObject).doSomething(argumentCaptor.capture());
assertThat(argumentCaptor.getValue(), equalTo(expected));