Java – Mockito. Verify method arguments

javajunitmockitounit testing

I've googled about this, but didn't find anything relevant. I've got something like this:

Object obj = getObject();
Mockeable mock= Mockito.mock(Mockeable.class);
Mockito.when(mock.mymethod(obj )).thenReturn(null);

Testeable testableObj = new Testeable();
testableObj.setMockeable(mock);
command.runtestmethod();

Now, I want to verify that mymethod(Object o), which is called inside runtestmethod(), was called with the Object o, not any other. But I always pass the test, whatever I put on the verification, for example, with:

Mockito.verify(mock.mymethod(Mockito.eq(obj)));

Mockito.verify(mock.mymethod(Mockito.eq(null)));

Mockito.verify(mock.mymethod(Mockito.eq("something_else")));

I always pass the test. How can I accomplish that verification (if possible)?

Thank you.

Best Answer

An alternative to ArgumentMatcher is ArgumentCaptor.

Official example:

ArgumentCaptor<Person> argument = ArgumentCaptor.forClass(Person.class);
verify(mock).doSomething(argument.capture());
assertEquals("John", argument.getValue().getName());

A captor can also be defined using the @Captor annotation:

@Captor ArgumentCaptor<Person> captor;
//... MockitoAnnotations.initMocks(this);
@Test public void test() {
    //...
    verify(mock).doSomething(captor.capture());
    assertEquals("John", captor.getValue().getName());
}

Related Solutions

Java – How to mock void methods with Mockito

Take a look at the Mockito API docs. As the linked document mentions (Point # 12) you can use any of the doThrow(),doAnswer(),doNothing(),doReturn() family of methods from Mockito framework to mock void methods.

For example,

Mockito.doThrow(new Exception()).when(instance).methodName();

or if you want to combine it with follow-up behavior,

Mockito.doThrow(new Exception()).doNothing().when(instance).methodName();

Presuming that you are looking at mocking the setter setState(String s) in the class World below is the code uses doAnswer method to mock the setState.

World mockWorld = mock(World.class); 
doAnswer(new Answer<Void>() {
    public Void answer(InvocationOnMock invocation) {
      Object[] args = invocation.getArguments();
      System.out.println("called with arguments: " + Arrays.toString(args));
      return null;
    }
}).when(mockWorld).setState(anyString());

Java – Making a mocked method return an argument that was passed to it

You can create an Answer in Mockito. Let's assume, we have an interface named Application with a method myFunction.

public interface Application {
  public String myFunction(String abc);
}

Here is the test method with a Mockito answer:

public void testMyFunction() throws Exception {
  Application mock = mock(Application.class);
  when(mock.myFunction(anyString())).thenAnswer(new Answer<String>() {
    @Override
    public String answer(InvocationOnMock invocation) throws Throwable {
      Object[] args = invocation.getArguments();
      return (String) args[0];
    }
  });

  assertEquals("someString",mock.myFunction("someString"));
  assertEquals("anotherString",mock.myFunction("anotherString"));
}

Since Mockito 1.9.5 and Java 8, you can also use a lambda expression:

when(myMock.myFunction(anyString())).thenAnswer(i -> i.getArguments()[0]);

Best Answer

Related Solutions

Java – How to mock void methods with Mockito

Java – Making a mocked method return an argument that was passed to it

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