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How to verify that a specific method was not called using Mockito?

Posted by: admin November 2, 2017 Leave a comment

Questions:

How to verify that a method is not called on an object’s dependency?

For example:

public interface Dependency {
    void someMethod();
}

public class Foo {
    public bar(final Dependency d) {
        ...
    }
}

With the Foo test:

    public class FooTest {
        @Test
        public void dependencyIsNotCalled() {
            final Foo foo = new Foo(...);
            final Dependency dependency = mock(Dependency.class);
            foo.bar(dependency);
            // verify here that someMethod was not called??
        }
    }

Answers:

Even more meaningful :

import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;

// ...

verify(dependency, never()).someMethod();

The documentation of this feature is there §4 “Verifying exact number of invocations / at least x / never”, and the never javadoc is here.

Questions:
Answers:

use the second argument on the Mockito.verify method, as in:

verify(dependency, Mockito.times(0)).someMethod()

Questions:
Answers:

As a more general pattern to follow, I tend to use an @After block in the test:

@After
public void after() {
    verifyNoMoreInteractions(<your mock1>, <your mock2>...);
}

Then the test is free to verify only what should be called.

Also, I found that I often forgot to check for “no interactions”, only to later discover that things were being called that shouldn’t have been.

So I find this pattern useful for catching all unexpected calls that haven’t specifically been verified.

Questions:
Answers:

Both the verifyNoMoreInteractions() and verifyZeroInteracions() method internally have the same implementation as:

public static transient void verifyNoMoreInteractions(Object mocks[])
{
    MOCKITO_CORE.verifyNoMoreInteractions(mocks);
}

public static transient void verifyZeroInteractions(Object mocks[])
{
    MOCKITO_CORE.verifyNoMoreInteractions(mocks);
}

so we can use any one of them on mock object or array of mock objects to check that no methods have been called using mock objects.