EasyMock - Quick Guide

What is Mocking?

Mocking is a way to test the functionality of a class in isolation. Mocking does not require a database connection or properties file read or file server read to test a functionality. Mock objects do the mocking of the real service. A mock object returns a dummy data corresponding to some dummy input passed to it.

EasyMock

EasyMock facilitates creating mock objects seamlessly. It uses Java Reflection in order to create mock objects for a given interface. Mock objects are nothing but proxy for actual implementations. Consider a case of Stock Service which returns the price details of a stock. During development, the actual stock service cannot be used to get real-time data. So we need a dummy implementation of the stock service. EasyMock can do the same very easily as its name suggests.

Benefits of EasyMock

No Handwriting – No need to write mock objects on your own.
Refactoring Safe – Renaming interface method names or reordering parameters will not break the test code as Mocks are created at runtime.
Return value support – Supports return values.
Exception support – Supports exceptions.
Order check support – Supports check on order of method calls.
Annotation support – Supports creating mocks using annotation.

Consider the following code snippet.

package com.howcodex.mock;

import java.util.ArrayList;
import java.util.List;
import org.EasyMock.EasyMock;

public class PortfolioTester {
   public static void main(String[] args){

      //Create a portfolio object which is to be tested		
      Portfolio portfolio = new Portfolio();

      //Creates a list of stocks to be added to the portfolio
      List stocks = new ArrayList();
      Stock googleStock = new Stock("1","Google", 10);
      Stock microsoftStock = new Stock("2","Microsoft",100);

      stocks.add(googleStock);
      stocks.add(microsoftStock);		

      //Create the mock object of stock service
      StockService stockServiceMock =
         EasyMock.createMock(StockService.class);

      // mock the behavior of stock service to return the value of various stocks
      EasyMock.expect(stockServiceMock.getPrice(googleStock)).andReturn(50.00);
      EasyMock.expect(stockServiceMock.getPrice(microsoftStock))
         .andReturn(1000.00);

      EasyMock.replay(stockServiceMock);

      //add stocks to the portfolio
      portfolio.setStocks(stocks);

      //set the stockService to the portfolio
      portfolio.setStockService(stockServiceMock);

      double marketValue = portfolio.getMarketValue();

      //verify the market value to be 
      //10*50.00 + 100* 1000.00 = 500.00 + 100000.00 = 100500
      System.out.println("Market value of the portfolio: "+ marketValue);
   }
}

Let's understand the important concepts of the above program. The complete code is available in the chapter First Application.

Portfolio – An object to carry a list of stocks and to get the market value computed using stock prices and stock quantity.
Stock – An object to carry the details of a stock such as its id, name, quantity, etc.
StockService – A stock service returns the current price of a stock.
EasyMock.createMock(...) – EasyMock created a mock of stock service.
EasyMock.expect(...).andReturn(...) – Mock implementation of getPrice method of stockService interface. For googleStock, return 50.00 as price.
EasyMock.replay(...) – EasyMock prepares the Mock object to be ready so that it can be used for testing.
portfolio.setStocks(...) – The portfolio now contains a list of two stocks.
portfolio.setStockService(...) - Assigns the stockService Mock object to the portfolio.
portfolio.getMarketValue()() – The portfolio returns the market value based on its stocks using the mock stock service.

EasyMock - Environment Setup

EasyMock is a framework for Java, so the very first requirement is to have JDK installed in your machine.

System Requirement

JDK	1.5 or above.
Memory	no minimum requirement.
Disk Space	no minimum requirement.
Operating System	no minimum requirement.

Step 1 – Verify Java Installation on Your Machine

Open the console and execute the following java command.

OS	Task	Command
Windows	Open Command Console	c:\> java -version
Linux	Open Command Terminal	$ java -version
Mac	Open Terminal	machine:~ joseph$ java -version

Let's verify the output for all the operating systems:

OS	Output
Windows	java version "1.6.0_21" Java(TM) SE Runtime Environment (build 1.6.0_21-b07) Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)
Linux	java version "1.6.0_21" Java(TM) SE Runtime Environment (build 1.6.0_21-b07) Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)
Mac	java version "1.6.0_21" Java(TM) SE Runtime Environment (build 1.6.0_21-b07) Java HotSpot(TM)64-Bit Server VM (build 17.0-b17, mixed mode, sharing)

Output

Windows

java version "1.6.0_21"

Java(TM) SE Runtime Environment (build 1.6.0_21-b07)

Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)

Linux

java version "1.6.0_21"

Java(TM) SE Runtime Environment (build 1.6.0_21-b07)

Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)

Mac

java version "1.6.0_21"

Java(TM) SE Runtime Environment (build 1.6.0_21-b07)

Java HotSpot(TM)64-Bit Server VM (build 17.0-b17, mixed mode, sharing)

If you do not have Java installed, install the Java Software Development Kit (SDK) from http://www.oracle.com/technetwork/java/javase/downloads/index.html.

We assume you have Java 1.6.0_21 installed on your system for this tutorial.

Step 2: Set JAVA Environment

Set the JAVA_HOME environment variable to point to the base directory location where Java is installed on your machine. For example,

OS	Output
Windows	Set the environment variable JAVA_HOME to C:\Program Files\Java\jdk1.6.0_21
Linux	export JAVA_HOME=/usr/local/java-current
Mac	export JAVA_HOME=/Library/Java/Home

Append the location of the Java compiler to your System Path.

OS	Output
Windows	Append the string ;C:\Program Files\Java\jdk1.6.0_21\bin to the end of the system variable, Path.
Linux	export PATH=$PATH:$JAVA_HOME/bin/
Mac	not required

Verify Java Installation using the command java -version as explained above.

Step 3: Download EasyMock Archive

Download the latest version of EasyMock from http://sourceforge.net/projects/easymock/files/EasyMock/3.2/easymock-3.2.zip/download. Save the zip folder on your C drive, let’s say, C:\>EasyMock.

OS	Archive name
Windows	easymock-3.2.zip
Linux	easymock-3.2.zip
Mac	easymock-3.2.zip

Step 4: Download EasyMock Dependencies

Download the latest version of cglib jar file from https://github.com/cglib/cglib/releases and copy it onto C:\>EasyMock folder. At the time of writing this tutorial, the latest version was 3.1.

Download the latest version of objenesis zip file from http://objenesis.org/download.html and copy it onto C:\>EasyMock folder. At the time of writing this tutorial, the latest version was 2.1. Extract objenesis-2.1.jar to C:\>EasyMock folder

Step 5: Set EasyMock Environment

Set the EasyMock_HOME environment variable to point to the base directory location where EasyMock and dependency jars are stored on your machine. The following table shows how to set the environment variable on different operating systems, assuming we've extracted easymock-3.2.jar, cglib-3.1.jar, and objenesis-2.1.jar onto C:\>EasyMock folder.

OS	Output
Windows	Set the environment variable EasyMock_HOME to C:\EasyMock
Linux	export EasyMock_HOME=/usr/local/EasyMock
Mac	export EasyMock_HOME=/Library/EasyMock

Step 6: Set CLASSPATH Variable

Set the CLASSPATH environment variable to point to the location where EasyMock and dependency jars are stored. The following table shows how to set the CLASSPATH variable on different operating systems.

OS	Output
Windows	Set the environment variable CLASSPATH to %CLASSPATH%;%EasyMock_HOME%\easymock-3.2.jar;%EasyMock_HOME%\cglib-3.1.jar;%EasyMock_HOME%\objenesis-2.1.jar;.;
Linux	export CLASSPATH=$CLASSPATH:$EasyMock_HOME/easymock-3.2.jar:$EasyMock_HOME/cglib-3.1.jar:$EasyMock_HOME/objenesis-2.1.jar:.
Mac	export CLASSPATH=$CLASSPATH:$EasyMock_HOME/easymock-3.2.jar:$EasyMock_HOME/cglib-3.1.jar:$EasyMock_HOME/objenesis-2.1.jar:.

Step 7: Download JUnit Archive

Download the latest version of JUnit jar file from https://github.com/junit-team/junit/wiki/Download-and-Install.Save the folder at the location C:\>Junit.

OS	Archive name
Windows	junit4.11.jar, hamcrest-core-1.2.1.jar
Linux	junit4.11.jar, hamcrest-core-1.2.1.jar
Mac	junit4.11.jar, hamcrest-core-1.2.1.jar

Step 8: Set JUnit Environment

Set the JUNIT_HOME environment variable to point to the base directory location where JUnit jars are stored on your machine. The following table shows how to set this environment variable on different operating systems, assuming we've stored junit4.11.jar and hamcrest-core-1.2.1.jar at C:\>Junit.

OS	Output
Windows	Set the environment variable JUNIT_HOME to C:\JUNIT
Linux	export JUNIT_HOME=/usr/local/JUNIT
Mac	export JUNIT_HOME=/Library/JUNIT

Step 9: Set CLASSPATH Variable

Set the CLASSPATH environment variable to point to the JUNIT jar location. The following table shows how it is done on different operating systems.

OS	Output
Windows	Set the environment variable CLASSPATH to %CLASSPATH%;%JUNIT_HOME%\junit4.11.jar;%JUNIT_HOME% \hamcrest-core-1.2.1.jar;.;
Linux	export CLASSPATH=$CLASSPATH:$JUNIT_HOME/junit4.11.jar:$JUNIT_HOME /hamcrest-core-1.2.1.jar:.
Mac	export CLASSPATH=$CLASSPATH:$JUNIT_HOME/junit4.11.jar:$JUNIT_HOME /hamcrest-core-1.2.1.jar:.

EasyMock - First Application

Before going into the details of the EasyMock Framework, let’s see an application in action. In this example, we've created a mock of Stock Service to get the dummy price of some stocks and unit tested a java class named Portfolio.

The process is discussed below in a step-by-step manner.

Step 1: Create a JAVA class to represent the Stock

Stock.java

public class Stock {
   private String stockId;
   private String name;	
   private int quantity;

   public Stock(String stockId, String name, int quantity){
      this.stockId = stockId;
      this.name = name;		
      this.quantity = quantity;		
   }

   public String getStockId() {
      return stockId;
   }

   public void setStockId(String stockId) {
      this.stockId = stockId;
   }

   public int getQuantity() {
      return quantity;
   }

   public String getTicker() {
      return name;
   }
}

Step 2: Create an interface StockService to get the price of a stock

StockService.java

public interface StockService {
   public double getPrice(Stock stock);
}

Step 3: Create a class Portfolio to represent the portfolio of any client

Portfolio.java

import java.util.List;
public class Portfolio {
   private StockService stockService;
   private List stocks;

   public StockService getStockService() {
      return stockService;
   }
   public void setStockService(StockService stockService) {
      this.stockService = stockService;
   }

   public List getStocks() {
      return stocks;
   }

   public void setStocks(List stocks) {
      this.stocks = stocks;
   }

   public double getMarketValue(){
      double marketValue = 0.0;
      for(Stock stock:stocks){
         marketValue += stockService.getPrice(stock) * stock.getQuantity();
      }
      return marketValue;
   }
}

Step 4: Test the Portfolio class

Let's test the Portfolio class, by injecting in it a mock of stockservice. Mock will be created by EasyMock.

PortfolioTester.java

import java.util.ArrayList;
import java.util.List;

import org.easymock.EasyMock;
public class PortfolioTester {
   Portfolio portfolio;	
   StockService stockService;

   public static void main(String[] args){
      PortfolioTester tester = new PortfolioTester();
      tester.setUp();
      System.out.println(tester.testMarketValue()?"pass":"fail");
   }

   public void setUp(){
      //Create a portfolio object which is to be tested		
      portfolio = new Portfolio();		
      
      //Create the mock object of stock service
      stockService = EasyMock.createMock(StockService.class);		
      
      //set the stockService to the portfolio
      portfolio.setStockService(stockService);
   }

   public boolean testMarketValue(){
      //Creates a list of stocks to be added to the portfolio
      List stocks = new ArrayList<Stock>();
      Stock googleStock = new Stock("1","Google", 10);
      Stock microsoftStock = new Stock("2","Microsoft",100);		
      stocks.add(googleStock);
      stocks.add(microsoftStock);

      //add stocks to the portfolio
      portfolio.setStocks(stocks);

      // mock the behavior of stock service to return the value of various stocks
      EasyMock.expect(stockService.getPrice(googleStock)).andReturn(50.00);
      EasyMock.expect(stockService.getPrice(microsoftStock)).andReturn(1000.00);		

      // activate the mock
      EasyMock.replay(stockService);		

      double marketValue = portfolio.getMarketValue();		
      return marketValue == 100500.0;
   }
}

Step 5: Verify the result

Compile the classes using javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Stock.java StockService.java Portfolio.java PortfolioTester.java

Now run the PortfolioTester to see the result:

C:\EasyMock_WORKSPACE>java PortfolioTester

Verify the Output

pass

EasyMock - JUnit Integration

In this chapter, we'll learn how to integrate JUnit and EasyMock together. For JUnit tutorial, please refer to JUnit. Here we will create a Math Application which uses CalculatorService to perform basic mathematical operations such as addition, subtraction, multiply, and division. We'll use EasyMock to mock the dummy implementation of CalculatorService. In addition, we've made extensive use of annotations to showcase their compatibility with both JUnit and EasyMock.

The process is discussed below in a step-by-step manner.

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

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

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);
   }
   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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
   }
}

Step 4: Create a class to execute to test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac CalculatorService.java MathApplication.java MathApplicationTester.java TestRunner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

EasyMock - Adding Behavior

EasyMock adds a functionality to a mock object using the methods expect() and expectLassCall(). Take a look at the following code snippet.

//add the behavior of calc service to add two numbers
EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

Here we've instructed EasyMock to give a behavior of adding 10 and 20 to the add method of calcService and as a result, to return the value of 30.00.

At this point of time, Mock simply recorded the behavior but it is not working as a mock object. After calling replay, it works as expected.

//add the behavior of calc service to add two numbers
EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

//activate the mock
//EasyMock.replay(calcService);

Example without EasyMock.Replay()

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

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

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);
   }
   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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

//@RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify the class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

      //activate the mock
      //EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
   }
}

Step 4: Execute test cases

Create a java class file named TestRunner in C:\>EasyMock_WORKSPACE to execute the test case(s).

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

testAdd(MathApplicationTester): expected:<0.0> but was:<30.0>
false

Example with EasyMock.Replay()

Step 1: Create an interface called CalculatorService to provide mathematical functions.

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.

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);
   }
   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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

      //activate the mock
      EasyMock.replay(calcService);	
		
      // test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result.

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

EasyMock - Verifying Behavior

EasyMock can ensure whether a mock is being used or not. It is done using the verify() method. Take a look at the following code snippet.

//activate the mock
EasyMock.replay(calcService);

//test the add functionality
Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

//verify call to calcService is made or not
EasyMock.verify(calcService);

Example without EasyMock.Verify()

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

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

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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      //EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

Example with EasyMock.Verify()

Step 1: Create an interface CalculatorService to provide mathematical functions

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

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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

testAdd(MathApplicationTester): 
   Expectation failure on verify:
      CalculatorService.add(10.0, 20.0): expected: 1, actual: 0
false

EasyMock - Expecting Calls

EasyMock provides a special check on the number of calls that can be made on a particular method. Suppose MathApplication should call the CalculatorService.serviceUsed() method only once, then it should not be able to call CalculatorService.serviceUsed() more than once.

//add the behavior of calc service to add two numbers and serviceUsed.
EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
calcService.serviceUsed();

//limit the method call to 1, no less and no more calls are allowed
EasyMock.expectLastCall().times(1);

Create CalculatorService interface as follows.

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);
   public void serviceUsed();
}

Example with calcService.serviceUsed() called once

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

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);
   public void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApplication

MathApplication.java

public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   public double add(double input1, double input2){		
      calcService.serviceUsed();
      return calcService.add(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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
      calcService.serviceUsed();
      EasyMock.expectLastCall().times(1);
      
      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

Example with calcService.serviceUsed() Called Twice

Step 1: Create an interface CalculatorService to provide mathematical functions.

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);
   public void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApplication.

MathApplication.java

public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   public double add(double input1, double input2){		
      calcService.serviceUsed();
      calcService.serviceUsed();
      return calcService.add(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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
      calcService.serviceUsed();
      EasyMock.expectLastCall().times(1);
      
      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac CalculatorService.java MathApplication.java MathApplicationTester.java TestRunner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

testAdd(com.howcodex.mock.MathApplicationTester):  
   Unexpected method call CalculatorService.serviceUsed():
      CalculatorService.add(10.0, 20.0): expected: 1, actual: 0
      CalculatorService.serviceUsed(): expected: 1, actual: 2
false

Example without Calling calcService.serviceUsed()

Step 1: Create an interface Calculator Service to provide mathematical functions

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);
   public void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApplication

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);		
   }
   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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
      calcService.serviceUsed();
      EasyMock.expectLastCall().times(1);
      
      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

testAdd(com.howcodex.mock.MathApplicationTester): 
   Expectation failure on verify:
      CalculatorService.serviceUsed(): expected: 1, actual: 0
false

EasyMock - Varying Calls

EasyMock provides the following additional methods to vary the expected call counts.

times (int min, int max) – expects between min and max calls.
atLeastOnce () – expects at least one call.
anyTimes () – expects an unrestricted number of calls.

Example with times (min,max)

Step 1: Create an interface CalculatorService to provide mathematical functions

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);
   public void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApplication

MathApplication.java

public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   public double add(double input1, double input2){
      calcService.serviceUsed();
      calcService.serviceUsed();
      calcService.serviceUsed();   
      return calcService.add(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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
      calcService.serviceUsed();
      EasyMock.expectLastCall().times(1,3);
      
      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

Example with atLeastOnce

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

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);
   public void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApplication

MathApplication.java

public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   public double add(double input1, double input2){
      calcService.serviceUsed();
      calcService.serviceUsed(); 
      return calcService.add(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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
      calcService.serviceUsed();
      EasyMock.expectLastCall().atLeastOnce();
      
      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

Example with anyTimes

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

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);
   public void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApplication

MathApplication.java

public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   public double add(double input1, double input2){
      calcService.serviceUsed();
      calcService.serviceUsed(); 
      return calcService.add(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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to 
         use the mock object
   @TestSubject
   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
      EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);
      calcService.serviceUsed();
      EasyMock.expectLastCall().anyTimes();
      
      //activate the mock
      EasyMock.replay(calcService);	
		
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

EasyMock - Exception Handling

EasyMock provides the capability to a mock to throw exceptions, so exception handling can be tested. Take a look at the following code snippet.

//add the behavior to throw exception

EasyMock.expect(calc Service.add(10.0,20.0)).and Throw(new Runtime Exception("Add operation not implemented"));

Here we've added an exception clause to a mock object. MathApplication makes use of calcService using its add method and the mock throws a RuntimeException whenever calcService.add() method is invoked.

Example

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

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

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);		
   }
   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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   // @TestSubject annotation is used to identify class which is going to
         use the mock object
   @TestSubject
   MathApplication mathApplication = new MathApplication();

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

   @Test(expected = RuntimeException.class)
   public void testAdd(){
      
      //add the behavior to throw exception
      EasyMock.expect(calcService.add(10.0,20.0)).andThrow(new
         RuntimeException("Add operation not implemented"));	     
      
      //activate the mock
      EasyMock.replay(calcService);			
      
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
      
      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

EasyMock - createMock

So far, we've used annotations to create mocks. EasyMock provides various methods to create mock objects. EasyMock.createMock() creates mocks without bothering about the order of method calls that the mock is going to make in due course of its action.

Syntax

calcService = EasyMock.createMock(CalculatorService.class);

Example

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

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

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);		
   }
   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 calculatorService. Mock will be created by EasyMock.

Here we've added two mock method calls, add() and subtract(), to the mock object via expect(). However during testing, we've called subtract() before calling add(). When we create a mock object using EasyMock.createMock(), the order of execution of the method does not matter.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   private MathApplication mathApplication;
   private CalculatorService calcService;
   
   @Before
   public void setUp(){
      mathApplication = new MathApplication();
      calcService = EasyMock.createMock(CalculatorService.class);
      mathApplication.setCalculatorService(calcService);
   }

   @Test
   public void testAddAndSubtract(){
     
      //add the behavior to add numbers
      EasyMock.expect(calcService.add(20.0,10.0)).andReturn(30.0);
      
      //subtract the behavior to subtract numbers
      EasyMock.expect(calcService.subtract(20.0,10.0)).andReturn(10.0);
      
      //activate the mock
      EasyMock.replay(calcService);	
	
      //test the subtract functionality
      Assert.assertEquals(mathApplication.subtract(20.0, 10.0),10.0,0);
      
      //test the add functionality
      Assert.assertEquals(mathApplication.add(20.0, 10.0),30.0,0);
      
      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

EasyMock - createStrictMock

EasyMock.createStrictMock() creates a mock and also takes care of the order of method calls that the mock is going to make in due course of its action.

Syntax

calcService = EasyMock.createStrictMock(CalculatorService.class);

Example

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

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

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);		
   }
   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 calculatorService. Mock will be created by EasyMock.

Here we've added two mock method calls, add() and subtract(), to the mock object via expect(). However during testing, we've called subtract() before calling add(). When we create a mock object using EasyMock.createStrictMock(), the order of execution of the method does matter.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   private MathApplication mathApplication;
   private CalculatorService calcService;
   
   @Before
   public void setUp(){
      mathApplication = new MathApplication();
      calcService = EasyMock.createStrictMock(CalculatorService.class);
      mathApplication.setCalculatorService(calcService);
   }

   @Test
   public void testAddAndSubtract(){
      
      //add the behavior to add numbers
      EasyMock.expect(calcService.add(20.0,10.0)).andReturn(30.0);
      
      //subtract the behavior to subtract numbers
      EasyMock.expect(calcService.subtract(20.0,10.0)).andReturn(10.0);
      
      //activate the mock
      EasyMock.replay(calcService);	
	
      //test the subtract functionality
      Assert.assertEquals(mathApplication.subtract(20.0, 10.0),10.0,0);
      
      //test the add functionality
      Assert.assertEquals(mathApplication.add(20.0, 10.0),30.0,0);
      
      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

testAddAndSubtract(com.howcodex.mock.MathApplicationTester): 
   Unexpected method call CalculatorService.subtract(20.0, 10.0):
      CalculatorService.add(20.0, 10.0): expected: 1, actual: 0
false

EasyMock - createNiceMock

EasyMock.createNiceMock() creates a mock and sets the default implementation of each method of the mock. If EasyMock.createMock() is used, then invoking the mock method throws assertion error.

Syntax

calcService = EasyMock.createNiceMock(CalculatorService.class);

Example

Step 1: Create an interface called CalculatorService to provide mathematical functions.

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

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);		
   }
   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 calculatorService. Mock will be created by EasyMock.

Here we've added one mock method call, add(), via expect(). However during testing, we've called subtract() and other methods as well. When we create a mock object using EasyMock.createNiceMock(), the default implementation with default values are available.

MathApplicationTester.java

import org.easymock.EasyMock;
import org.easymock.EasyMockRunner;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(EasyMockRunner.class)
public class MathApplicationTester {
	
   private MathApplication mathApplication;
   
   private CalculatorService calcService;

   @Before
   public void setUp(){
      mathApplication = new MathApplication();
      calcService = EasyMock.createNiceMock(CalculatorService.class);
      mathApplication.setCalculatorService(calcService);
   }

   @Test
   public void testCalcService(){
      
      //add the behavior to add numbers
      EasyMock.expect(calcService.add(20.0,10.0)).andReturn(30.0);
      
      //activate the mock
      EasyMock.replay(calcService);	
      
      //test the add functionality
      Assert.assertEquals(mathApplication.add(20.0, 10.0),30.0,0);
      
      //test the subtract functionality
      Assert.assertEquals(mathApplication.subtract(20.0, 10.0),0.0,0);
      
      //test the multiply functionality
      Assert.assertEquals(mathApplication.divide(20.0, 10.0),0.0,0);		
      
      //test the divide functionality
      Assert.assertEquals(mathApplication.multiply(20.0, 10.0),0.0,0);

      //verify call to calcService is made or not
      EasyMock.verify(calcService);
   }
}

Step 4: Execute test cases

Create a java class file named TestRunner inC:\> EasyMock_WORKSPACE to execute Test case(s).

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

EasyMock - EasyMockSupport

EasyMockSupport is a utility or helper class for test classes. It provides the following functionalities:

replayAll() – Registers all the created mocks in one batch.
verifyAll() – Verifies all the mock operations in one batch.
resetAll() – Resets all the mock operations in one batch.

Example

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

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

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);		
   }
   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 calculatorService. Mock will be created by EasyMock.

MathApplicationTester.java

import org.easymock.EasyMockRunner;
import org.easymock.EasyMockSupport;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(EasyMockRunner.class)
public class MathApplicationTester extends EasyMockSupport {

   private MathApplication mathApplication1;
   private MathApplication mathApplication2;

   private CalculatorService calcService1;
   private CalculatorService calcService2;

   @Before
   public void setUp(){
      mathApplication1 = new MathApplication();
      mathApplication2 = new MathApplication();
      calcService1 = createNiceMock(CalculatorService.class);
      calcService2 = createNiceMock(CalculatorService.class);
      mathApplication1.setCalculatorService(calcService1);
      mathApplication2.setCalculatorService(calcService2);
   }

   @Test
   public void testCalcService(){
      
      //activate all mocks
      replayAll();	
      
      //test the add functionality
      Assert.assertEquals(mathApplication1.add(20.0, 10.0),0.0,0);
      
      //test the subtract functionality
      Assert.assertEquals(mathApplication1.subtract(20.0, 10.0),0.0,0);
      
      //test the multiply functionality
      Assert.assertEquals(mathApplication1.divide(20.0, 10.0),0.0,0);		
      //test the divide functionality
      Assert.assertEquals(mathApplication1.multiply(20.0, 10.0),0.0,0);

      //test the add functionality
      Assert.assertEquals(mathApplication2.add(20.0, 10.0),0.0,0);
      
      //test the subtract functionality
      Assert.assertEquals(mathApplication2.subtract(20.0, 10.0),0.0,0);
      
      //test the multiply functionality
      Assert.assertEquals(mathApplication2.divide(20.0, 10.0),0.0,0);		
      
      //test the divide functionality
      Assert.assertEquals(mathApplication2.multiply(20.0, 10.0),0.0,0);

      //verify all the mocks
      verifyAll();
   }
}

Step 4: Execute test cases

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

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 javac compiler as follows:

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

Now run the Test Runner to see the result:

C:\EasyMock_WORKSPACE>java TestRunner

Verify the output.

true

Previous Page Print Page

EasyMock - Quick Guide

EasyMock - Overview

What is Mocking?

EasyMock

Benefits of EasyMock

EasyMock - Environment Setup

System Requirement

Step 1 – Verify Java Installation on Your Machine

Step 2: Set JAVA Environment

Step 3: Download EasyMock Archive

Step 4: Download EasyMock Dependencies

Step 5: Set EasyMock Environment

Step 6: Set CLASSPATH Variable

Step 7: Download JUnit Archive

Step 8: Set JUnit Environment

Step 9: Set CLASSPATH Variable

EasyMock - First Application

Step 1: Create a JAVA class to represent the Stock

Step 2: Create an interface StockService to get the price of a stock

Step 3: Create a class Portfolio to represent the portfolio of any client

Step 4: Test the Portfolio class

Step 5: Verify the result

EasyMock - JUnit Integration

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

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Create a class to execute to test cases

Step 5: Verify the Result

EasyMock - Adding Behavior

Example without EasyMock.Replay()

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

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

Example with EasyMock.Replay()

Step 1: Create an interface called CalculatorService to provide mathematical functions.

Step 2: Create a JAVA class to represent MathApplication.

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

EasyMock - Verifying Behavior

Example without EasyMock.Verify()

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

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

Example with EasyMock.Verify()

Step 1: Create an interface CalculatorService to provide mathematical functions

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

EasyMock - Expecting Calls

Example with calcService.serviceUsed() called once

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

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

Example with calcService.serviceUsed() Called Twice

Step 1: Create an interface CalculatorService to provide mathematical functions.

Step 2: Create a JAVA class to represent MathApplication.

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

Example without Calling calcService.serviceUsed()

Step 1: Create an interface Calculator Service to provide mathematical functions

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result

EasyMock - Varying Calls

Example with times (min,max)

Step 1: Create an interface CalculatorService to provide mathematical functions

Step 2: Create a JAVA class to represent MathApplication

Step 3: Test the MathApplication class

Step 4: Execute test cases

Step 5: Verify the Result