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

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);
}

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.

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 calpng add(). When we create a mock object using EasyMock.createMock(), the order of execution of the method does not matter.

File: MathApppcationTester.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)
pubpc class MathApppcationTester {
   private MathApppcation mathApppcation;
   private CalculatorService calcService;
   
   @Before
   pubpc void setUp(){
      mathApppcation = new MathApppcation();
      calcService = EasyMock.createMock(CalculatorService.class);
      mathApppcation.setCalculatorService(calcService);
   }
   @Test
   pubpc 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 functionapty
      Assert.assertEquals(mathApppcation.subtract(20.0, 10.0),10.0,0);
      
      //test the add functionapty
      Assert.assertEquals(mathApppcation.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).

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 MathApppcationTester.java

Now run the Test Runner to see the result −

C:EasyMock_WORKSPACE>java TestRunner

Output

Verify the output.

true