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javajunitmockitojunit4hamcrest

Mockito: verify parameter without having to cast it

I have a service class with the following method:

void doSomething(List<String> list)

I mock this class and I want to verify that a list which is passed as a parameter has only one element. I do it like this:

verify(myService).doSomething((List<String>) argThat(hasSize(1))))

As you see I have to cast the argument to List<String> otherwise it doesn't get compiled:

incompatible types: inferred type does not conform to upper bound(s)
  inferred: java.util.Collection<? extends java.lang.Object>
  upper bound(s): java.util.List<java.lang.String>,java.lang.Object

Question: How can I verify the call without casting? I want to keep things simple, readable and elegant.

Solution

  • I prefer this solution:

    final ArgumentCaptor<List> argumentCaptor = ArgumentCaptor.forClass(List.class);

verify(myService).doSomething(argumentCaptor.capture());

assertThat(argumentCaptor.getValue().size()).isEqualTo(1);