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Mockito. Verify method arguments

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)));

or

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

or

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

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

Thank you.


N
Nikunj Undhad

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());
}

Thanks for sample! Never used it. Feels to be a bit weird to have things like captor in the code, but it helped.
Haha, I did not understand the question, but the answer helped me a lot. Thanks :-)
Important: Call verify()/capture() after using the mock. I was thinking it has to be "installed" before...
Thanks for this answer!
This is a great answer!! Thank you very much!
e
epox

argThat plus lambda

that is how you can fail your argument verification:

    verify(mock).mymethod(argThat(
                            x -> false ));

where

import static org.mockito.ArgumentMatchers.argThat;
import static org.mockito.Mockito.verify;

argThat plus asserts

the above test will "say" Expected: lambda$... Was: YourClass.toSting.... You can get a more specific cause of the failure if to use asserts in the the lambda:

    verify(mock).mymethod(argThat( x -> {
      assertThat(x).isNotNull();
      assertThat(x.description).contains("KEY");
      return true;
    }));

❗️BUT❗️: THIS ONLY WORKS WHEN

THE CALL IS EXPECTED 1 TIME, or

the call is expected 2+ times, but all the times the verifier matches (returns true).

If the verified method called 2+ times, mockito passes all the called combinations to each verifier. So mockito expects your verifier silently returns true for one of the argument set, and false (no assert exceptions) for other valid calls. That expectation is not a problem for 1 method call - it should just return true 1 time.

import static org.assertj.core.api.Assertions.assertThat;
import static org.mockito.ArgumentMatchers.argThat;
import static org.mockito.Mockito.verify;

Now the failed test will say: Expected: Obj.description to contain 'KEY'. Was: 'Actual description'. NOTE: I used assertJ asserts, but it's up to you which assertion framework to use.

direct argument

Mokito compares direct arguments using equals():

verify(mock).mymethod(expectedArg);
// NOTE:   ^ where the parentheses must be closed.

eq matcher

Never use eq for a single arg. Use the aforementioned direct argument.

Mokito compares direct arguments using equals()

Reason: eq would be a SonarQube / SonarClound violation: https://rules.sonarsource.com/java/tag/mockito/RSPEC-6068

argThat with multiple arguments.

If you use argThat, all arguments must be provided with matches. E.g. if, in a different case, you had another method with 2 arguments:

    verify(mock).mymethod2(eq("VALUE_1"), argThat((x)->false));
    // above is correct as eq() is also an argument matcher.

verify(mock).mymethod2("VALUE_1", argThat((x)->false)); // above is incorrect; an exception will be thrown, as the first arg. is given without an argument matcher.

where:

import static org.mockito.ArgumentMatchers.argThat;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.verify;

THE ROOT CAUSE of original question failure was the wrong place of the parentheses:

verify(mock.mymethod.... That was wrong. The right would be:

verify(mock).*


This one is my favourite answer, works & much more elegant than the others.
how this is work? verify(mock).mymethod(eq("VALUE_1"), argThat((x)->false)); "mymethod" has one arg how we are sending two?
@max, right catch. The example was under ... with multiple arguments section, so, yes, you are right, it has no relation to the original mymethod(arg0) case. It only makes sense for a different (2 args) case. Renaming it to mymethod2, to avoid the confusion, a little bit.
M
Matthew Kirkley

Are you trying to do logical equality utilizing the object's .equals method? You can do this utilizing the argThat matcher that is included in Mockito

import static org.mockito.Matchers.argThat

Next you can implement your own argument matcher that will defer to each objects .equals method

private class ObjectEqualityArgumentMatcher<T> extends ArgumentMatcher<T> {
    T thisObject;

    public ObjectEqualityArgumentMatcher(T thisObject) {
        this.thisObject = thisObject;
    }

    @Override
    public boolean matches(Object argument) {
        return thisObject.equals(argument);
    }
}

Now using your code you can update it to read...

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

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

verify(mock).mymethod(argThat(new ObjectEqualityArgumentMatcher<Object>(obj)));

If you are just going for EXACT equality (same object in memory), just do

verify(mock).mymethod(obj);

This will verify it was called once.


You could use the build in ReflectionEquals class for that purposes.
+1 for your answer. But I'd like to add that verify(mock).mymethod(obj); doesn't check for EXACT equality (same object in memory). Instead it uses the objects equals-method which could have been overwridden.
You can also create an anonymous implementation of ArgumentMatcher to be less verbose.
More detail: by default verify() invokes the /inbound argument's/ equals() method, rather than the /recorded object's/ equals() method. this is irrelevant unless you are trying to confirm that your test subject returns a specific object instance, and the subject returns what is supposed to be a transparent decorator of that instance instead. The verify argument's equals() would not know of the decorator; while the decorator's equals() would be rewritten to tolerate the original. In this instance your test will falsely fail.
B
Bozho

You don't need the eq matcher if you don't use other matchers.

You are not using the correct syntax - your method call should be outside the .verify(mock). You are now initiating verification on the result of the method call, without verifying anything (not making a method call). Hence all tests are passing.

You code should look like:

Mockito.verify(mock).mymethod(obj);
Mockito.verify(mock).mymethod(null);
Mockito.verify(mock).mymethod("something_else");

I'd tried that before, and again now to be sure. I still have the same problem, the test always passes.
It verifeis by reference
@cnexans , no it doesn't verify by reference. Moreover, eq would be the SonarQube/SonarCloud code smell alert: rules.sonarsource.com/java/tag/mockito/RSPEC-6068
F
Free-Minded

I have used Mockito.verify in this way

@UnitTest
public class JUnitServiceTest
{
    @Mock
    private MyCustomService myCustomService;


    @Test
    public void testVerifyMethod()
    {
       Mockito.verify(myCustomService, Mockito.never()).mymethod(parameters); // method will never call (an alternative can be pick to use times(0))
       Mockito.verify(myCustomService, Mockito.times(2)).mymethod(parameters); // method will call for 2 times
       Mockito.verify(myCustomService, Mockito.atLeastOnce()).mymethod(parameters); // method will call atleast 1 time
       Mockito.verify(myCustomService, Mockito.atLeast(2)).mymethod(parameters); // method will call atleast 2 times
       Mockito.verify(myCustomService, Mockito.atMost(3)).mymethod(parameters); // method will call at most 3 times
       Mockito.verify(myCustomService, Mockito.only()).mymethod(parameters); //   no other method called except this
    }
}

r
rit

Have you checked the equals method for the mockable class? If this one returns always true or you test the same instance against the same instance and the equal method is not overwritten (and therefor only checks against the references), then it returns true.


N
Nils Renaud

The other method is to use the org.mockito.internal.matchers.Equals.Equals method instead of redefining one :

verify(myMock).myMethod((inputObject)Mockito.argThat(new Equals(inputObjectWanted)));

W
Will

Many of the above answers confused me but I suspect it may be due to older versions of Mockito. This answer is accomplished using

Java 11

Mockito 3.1.0

SpringBoot 2.2.7.RELEASE

JUnit5

Using ArgumentCaptor I have done it this way:

@Mock
MyClientService myClientService;
@InjectMocks 
MyService myService;


@Test
void myTest() {

  ArgumentCaptor<String> captorParam1 = ArgumentCaptor.forClass(String.class);
  ArgumentCaptor<String> captorParam2 = ArgumentCaptor.forClass(String.class);

  Mockito.when(myClientService.doSomething(captorParam1.capture(), captorParam2.capture(), ArgumentMatchers.anyString()))
      .thenReturn(expectedResponse);

  assertDoesNotThrow(() -> myService.process(data));

  assertEquals("param1", captorParam1.getValue());
  assertEquals("param2", captorParam2.getValue());

  verify(myClientService, times(1))
    .doSomething(anyString(), anyString(), anyString());
}

c
cbbcloud

Have you tried it with the same() matcher? As in:

verify(mockObj).someMethod(same(specificInstance));

I had the same problem. I tried it with the eq() matcher as well as the refEq() matcher but I always had false positives. When I used the same() matcher, the test failed when the arguments were different instances and passed once the arguments were the same instance.


L
Labu
Verify(a).aFunc(eq(b))

In pseudocode:

When in the instance a - a function named aFunc is called. Verify this call got an argument which is equal to b.


R
Ray

You can also use TypeSafeDiagnosingMatcher

    private Matcher<GetPackagesRequest> expectedPackageRequest(final AvailabilityRequest request) {
    return new TypeSafeDiagnosingMatcher<GetPackagesRequest>() {

        StringBuilder text = new StringBuilder(500);

        @Override
        protected boolean matchesSafely(GetPackagesRequest req, Description desc) {
            String productCode = req.getPackageIds().iterator().next().getValue();
            if (productCode.equals(request.getSupplierProductCode())) {
                text.append("ProductCode not equal! " + productCode + " , " + request.getSupplierProductCode());
                return true;
            }

            text.append(req.toString());
            return false;
        }

        @Override
        public void describeTo(Description d) {
            d.appendText(text.toString());
        }
    };
}

Then verify that invocation:

Mockito.verify(client).getPackages(Mockito.argThat(expectedPackageRequest(request)));