Mockito: Some regularly used features

        Mockito is a very useful unit test framework and it has now become vastly famous in java software developers community. Few advantages of Mockito from its predecessors  is that Mockito can create mock objects of concrete classes (earlier unit test frameworks only could mock interfaces) and it is very simple and understandable.

        This article only highlights few useful techniques that are used when using Mockito and is only for the readers who already has experience in Mockito. But for beginners, there are many small tutorials available on the web to get things going.

Mock a method using Mockito

ConcreteClass mockObject = ConcreteMockito.mock(ConcreteClass.class)

Mockito.when(mockObject.testMethod()).thenReturn(testObject);

Check whether a given method is invoked

    

In the following code we check whether testMethod() is called once.

Mockito.verify(concreteClass, Mockito.times(1)).testMethod();

Check whether an exception is thrown

In following code the test will fail if testMethod() does not throw an exception.

try

{

         instance.testMethod();

         fail();

}

catch(SpiderException )

{

         assertTrue(expectedMessage.equals(ex.information));

}

Mock to return the same argument that passed into the method

In the following method the testMethod() is mocked in a way that it returns the same String array which was passed to it as a parameter.

Mockito.when(instance.testMethod(Mockito.any(String[].class)))

        .thenAnswer(new Answer<String[]>() {

        public String[] answer(InvocationOnMock invocation) throws Throwable {

                Object[] args = invocation.getArguments();

                return (String[]) args[0];

       }

});