Mockito - Verifying Behavior - Adglob Infosystem Pvt Ltd

Mockito can ensure whether a mock method is being called with required arguments or not. It is done using the verify() method. Take a look at the following code snippet.

//test the add functionality

Assert.assertEquals(calcService.add(10.0, 20.0),30.0,0);

//verify call to calcService is made or not with same arguments.

verify(calcService).add(10.0, 20.0);

Example – verify() with same arguments

Step 1 − Create an interface called CalculatorService to provide mathematical functions

File: CalculatorService.java

public interface CalculatorService {

   public double add(double input1, double input2);

   public double subtract(double input1, double input2);

   public double multiply(double input1, double input2);

   public double divide(double input1, double input2);

Step 2 − Create a JAVA class to represent MathApplication

File: MathApplication.java

public class MathApplication {

   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){

      this.calcService = calcService;

   public double add(double input1, double input2){

      //return calcService.add(input1, input2);

      return input1 + input2;

   public double subtract(double input1, double input2){

      return calcService.subtract(input1, input2);

   public double multiply(double input1, double input2){

      return calcService.multiply(input1, input2);

   public double divide(double input1, double input2){

      return calcService.divide(input1, input2);

Step 3 − Test the MathApplication class

Let’s test the MathApplication class, by injecting in it a mock of calculator service. Mock will be created by Mockito.

File: MathApplicationTester.java

import static org.mockito.Mockito.verify;

import static org.mockito.Mockito.when;

import org.junit.Assert;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.mockito.InjectMocks;

import org.mockito.Mock;

import org.mockito.runners.MockitoJUnitRunner;

// @RunWith attaches a runner with the test class to initialize the test data

@RunWith(MockitoJUnitRunner.class)

public class MathApplicationTester {

   //@InjectMocks annotation is used to create and inject the mock object

   @InjectMocks

   MathApplication mathApplication = new MathApplication();

   //@Mock annotation is used to create the mock object to be injected

   @Mock

   CalculatorService calcService;

   @Test

   public void testAdd(){

      //add the behavior of calc service to add two numbers

      when(calcService.add(10.0,20.0)).thenReturn(30.00);

      //test the add functionality

      Assert.assertEquals(calcService.add(10.0, 20.0),30.0,0);

      //verify the behavior

      verify(calcService).add(10.0, 20.0);

Step 4 − Execute test cases

Create a java class file named TestRunner in C:\> Mockito_WORKSPACE to execute Test case(s).

File: TestRunner.java

import org.junit.runner.JUnitCore;

import org.junit.runner.Result;

import org.junit.runner.notification.Failure;

public class TestRunner {

   public static void main(String[] args) {

      Result result = JUnitCore.runClasses(MathApplicationTester.class);

      for (Failure failure : result.getFailures()) {

         System.out.println(failure.toString());

      System.out.println(result.wasSuccessful());

Step 5 − Verify the Result

Compile the classes using the javac compiler as follows −

C:\Mockito_WORKSPACE>javac CalculatorService.java MathApplication.

   java MathApplicationTester.java TestRunner.java

Now run the Test Runner to see the result

C:\Mockito_WORKSPACE>java TestRunner

Verify the output.

true

Example – verify() with different arguments

Step 1 − Create an interface CalculatorService to provide mathematical functions