Mockito: Verifying with generic parameters

Question

With Mockito I can do the following:

verify(someService).process(any(Person.class));

But how do I write this if process takes a Collection<Person> instead? Can't figure out how to write it correctly. Just getting syntax errors...

Solution 1

Try:

verify(someService).process(Matchers.<Collection<Person>>any());

Actually, IntelliJ automatically suggested this fix when I typed any()... Unfortunately you cannot use static import in this case.

Solution 2

Try :

verify(someService).process(anyCollectionOf(Person.class));

Since version 1.8 Mockito introduces

public static <T> Collection<T> anyCollectionOf(Class<T> clazz);

Solution 3

if you use a own method, you can even use static import:

private Collection<Person> anyPersonCollection() {
    return any();
}

Then you can use

verify(someService).process(anyPersonCollection());

Comments

[Rogério]

Actually, it could be expressed with a "type literal" object if the API accepted it: any(new TypeLiteral<Collection<Person>>() {}). Not pretty, of course, but it does work since all the type information is available at runtime (through Reflection or a bytecode library).

[Waldheinz]

@Rogerio: you are right, and it seems Mockito indeed supports this now. Haven't used it in a while...

[Cristiano Fontes]

Thanks it works... but God it looks horrible, there have to be a nicer way to right that...

[Adam Parkin]

Thumbs up on the only solution that answers the question as stated as opposed to targeting the special case of matching containers.

[scubbo]

This answer is now incorrect. The answer below gives a better solution.

[Elijah Lofgren]

For others who come to this and need it, there's also an anyListOf() in addition to anyCollectionOf(), see: stackoverflow.com/a/10512526/908677

[Gabriel Falcone]

I may be mistaken but I do not think this is the correct answer. Although it removes the warning, the verification switches from "any(Collection.class)" to any(), which does not verify anything. At least before there was a class check. Isn't it?

[Rana Ghosh]

How did you get intellij to automatically suggest that to you?

[Naxos84]

anyCollectionOf(Class<T> clazz) will be removed in Mockito 3.0 and java8. There will be a new method: anyOptional(Class<T> class) see: github.com/mockito/mockito/issues/308

[Ray]

Matchers is deprecated, should now use ArgumentMatchers.