EasyMock - Expecting Calls

EasyMock provides a special check on the number of calls that can be made on a particular method. Suppose MathApppcation 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();

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

Create CalculatorService interface as follows.

File: CalculatorService.java

pubpc interface CalculatorService {
   pubpc double add(double input1, double input2);
   pubpc double subtract(double input1, double input2);
   pubpc double multiply(double input1, double input2);
   pubpc double spanide(double input1, double input2);
   pubpc void serviceUsed();
}

Example with calcService.serviceUsed() called once

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

File: CalculatorService.java

pubpc interface CalculatorService {
   pubpc double add(double input1, double input2);
   pubpc double subtract(double input1, double input2);
   pubpc double multiply(double input1, double input2);
   pubpc double spanide(double input1, double input2);
   pubpc void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApppcation

File: MathApppcation.java

pubpc class MathApppcation {
   private CalculatorService calcService;
   pubpc void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   pubpc double add(double input1, double input2){		
      calcService.serviceUsed();
      return calcService.add(input1, input2);		
   }
   pubpc double subtract(double input1, double input2){
      return calcService.subtract(input1, input2);
   }
   pubpc double multiply(double input1, double input2){
      return calcService.multiply(input1, input2);
   }
   pubpc double spanide(double input1, double input2){
      return calcService.spanide(input1, input2);
   }
}

Step 3: Test the MathApppcation class

Let s test the MathApppcation class, by injecting in it a mock of calculatorService. Mock will be created by EasyMock.

File: MathApppcationTester.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 initiapze the test data
@RunWith(EasyMockRunner.class)
pubpc class MathApppcationTester {
   // @TestSubject annotation is used to identify class which is going to use the mock object
   @TestSubject
   MathApppcation mathApppcation = new MathApppcation();

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

   @Test
   pubpc 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 functionapty
      Assert.assertEquals(mathApppcation.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).

File: TestRunner.java

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

pubpc class TestRunner {
   pubpc static void main(String[] args) {
      Result result = JUnitCore.runClasses(MathApppcationTester.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 Apppcation.java Math Apppcation Tester.java Test Runner.java

Now run the Test Runner to see the result −

C:EasyMock_WORKSPACE>java TestRunner

Output

Verify the output.

true

Example with calcService.serviceUsed() Called Twice

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

File: CalculatorService.java

pubpc interface CalculatorService {
   pubpc double add(double input1, double input2);
   pubpc double subtract(double input1, double input2);
   pubpc double multiply(double input1, double input2);
   pubpc double spanide(double input1, double input2);
   pubpc void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApppcation.

File: MathApppcation.java

pubpc class MathApppcation {
   private CalculatorService calcService;
   pubpc void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   pubpc double add(double input1, double input2){		
      calcService.serviceUsed();
      calcService.serviceUsed();
      return calcService.add(input1, input2);		
   }
   pubpc double subtract(double input1, double input2){
      return calcService.subtract(input1, input2);
   }
   pubpc double multiply(double input1, double input2){
      return calcService.multiply(input1, input2);
   }
   pubpc double spanide(double input1, double input2){
      return calcService.spanide(input1, input2);
   }
}

Step 3: Test the MathApppcation class

Let s test the MathApppcation class, by injecting in it a mock of calculatorService. Mock will be created by EasyMock.

File: MathApppcationTester.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 initiapze the test data
@RunWith(EasyMockRunner.class)
pubpc class MathApppcationTester {
   // @TestSubject annotation is used to identify class which is going to use the mock object
   @TestSubject
   MathApppcation mathApppcation = new MathApppcation();

   //@Mock annotation is used to create the mock object to be injected
   @Mock
   CalculatorService calcService;
	
   @Test
   pubpc 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 functionapty
      Assert.assertEquals(mathApppcation.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).

File: TestRunner.java

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

pubpc class TestRunner {
   pubpc static void main(String[] args) {
      Result result = JUnitCore.runClasses(MathApppcationTester.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 MathApppcation.java MathApppcationTester.java TestRunner.java

Now run the Test Runner to see the result −

C:EasyMock_WORKSPACE>java TestRunner

Output

Verify the output.

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

Example without Calpng calcService.serviceUsed()

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

File: CalculatorService.java

pubpc interface CalculatorService {
   pubpc double add(double input1, double input2);
   pubpc double subtract(double input1, double input2);
   pubpc double multiply(double input1, double input2);
   pubpc double spanide(double input1, double input2);
   pubpc void serviceUsed();
}

Step 2: Create a JAVA class to represent MathApppcation

File: MathApppcation.java

pubpc class MathApppcation {
   private CalculatorService calcService;
   pubpc void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   pubpc double add(double input1, double input2){		
      return calcService.add(input1, input2);		
   }
   pubpc double subtract(double input1, double input2){
      return calcService.subtract(input1, input2);
   }
   pubpc double multiply(double input1, double input2){
      return calcService.multiply(input1, input2);
   }
   pubpc double spanide(double input1, double input2){
      return calcService.spanide(input1, input2);
   }
}

Step 3: Test the MathApppcation class

Let s test the MathApppcation class, by injecting in it a mock of calculatorService. Mock will be created by EasyMock.

File: MathApppcationTester.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 initiapze the test data
@RunWith(EasyMockRunner.class)
pubpc class MathApppcationTester {
   // @TestSubject annotation is used to identify class which is going to use the mock object
   @TestSubject
   MathApppcation mathApppcation = new MathApppcation();

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

   @Test
   pubpc 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 functionapty
      Assert.assertEquals(mathApppcation.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).

File: TestRunner.java

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

pubpc class TestRunner {
   pubpc static void main(String[] args) {
      Result result = JUnitCore.runClasses(MathApppcationTester.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 Apppcation.java Math Apppcation Tester.java Test Runner.java

Now run the Test Runner to see the result −

C:EasyMock_WORKSPACE>java TestRunner

Output

Verify the output.

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