Verify object attribute value with mockito – Dev

The best answers to the question “Verify object attribute value with mockito” in the category Dev.

QUESTION:

I have a method call which I want to mock with mockito. To start with I have created and injected an instance of an object on which the method will be called. My aim is to verify one of the object in method call.

Is there a way that mockito allows you to assert or verify the object and it’s attributes when the mock method is called?

example

Mockito.verify(mockedObject)
       .someMethodOnMockedObject(
              Mockito.<SomeObjectAsArgument>anyObject())

Instead of doing anyObject() i want to check that argument object contains some particular fields

Mockito.verify(mockedObject)
       .someMethodOnMockedObject(
              Mockito.<SomeObjectAsArgument>**compareWithThisObject()**)

ANSWER:

I think the easiest way for verifying an argument object is to use the refEq method:

Mockito.verify(mockedObject).someMethodOnMockedObject(ArgumentMatchers.refEq(objectToCompareWith));

It can be used even if the object doesn’t implement equals(), because reflection is used. If you don’t want to compare some fields, just add their names as arguments for refEq.

ANSWER:

New feature added to Mockito makes this even easier,

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

Take a look at Mockito documentation


In case when there are more than one parameters, and capturing of only single param is desired, use other ArgumentMatchers to wrap the rest of the arguments:

verify(mock).doSomething(eq(someValue), eq(someOtherValue), argument.capture());
assertEquals("John", argument.getValue().getName());

ANSWER:

This is answer based on answer from iraSenthil but with annotation (Captor). In my opinion it has some advantages:

  • it’s shorter
  • it’s easier to read
  • it can handle generics without warnings

Example:

@RunWith(MockitoJUnitRunner.class)
public class SomeTest{

    @Captor
    private ArgumentCaptor<List<SomeType>> captor;

    //...

    @Test 
    public void shouldTestArgsVals() {
        //...
        verify(mockedObject).someMethodOnMockedObject(captor.capture());

        assertThat(captor.getValue().getXXX(), is("expected"));
    }
}

ANSWER:

One more possibility, if you don’t want to use ArgumentCaptor (for example, because you’re also using stubbing), is to use Hamcrest Matchers in combination with Mockito.

import org.mockito.Mockito
import org.hamcrest.Matchers
...

Mockito.verify(mockedObject).someMethodOnMockedObject(MockitoHamcrest.argThat(
    Matchers.<SomeObjectAsArgument>hasProperty("propertyName", desiredValue)));