Mockito - Ordered Verification

Mockito provides Inorder class which takes care of the order of method calls that the mock is going to make in due course of its action.
//create an inOrder verifier for a single mock
InOrder inOrder = inOrder(calcService);

//following will make sure that add is first called then subtract is called.
inOrder.verify(calcService).add(20.0,10.0);
inOrder.verify(calcService).subtract(20.0,10.0);

Step 1 − Create an interface called CalculatorService to provide mathematical functions
File: CalculatorService.java
public interface CalculatorService {
   public double add(double input1, double input2);
   public double subtract(double input1, double input2);
   public double multiply(double input1, double input2);
   public double divide(double input1, double input2);
}
Step 2 − Create a JAVA class to represent MathApplication
File: MathApplication.java
public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   
   public double add(double input1, double input2){
      return calcService.add(input1, input2);		
   }
   
   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 Mockito.
Here we've added two mock method calls, add() and subtract(), to the mock object via when(). However during testing, we've called subtract() before calling add(). When we create a mock object using Mockito, the order of execution of the method does not matter. Using InOrder class, we can ensure call order.
File: MathApplicationTester.java
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.inOrder;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InOrder;
import org.mockito.runners.MockitoJUnitRunner;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(MockitoJUnitRunner.class)
public class MathApplicationTester {
	
   private MathApplication mathApplication;
   private CalculatorService calcService;

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

   @Test
   public void testAddAndSubtract(){

      //add the behavior to add numbers
      when(calcService.add(20.0,10.0)).thenReturn(30.0);

      //subtract the behavior to subtract numbers
      when(calcService.subtract(20.0,10.0)).thenReturn(10.0);

      //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),10.0,0);

      //create an inOrder verifier for a single mock
      InOrder inOrder = inOrder(calcService);

      //following will make sure that add is first called then subtract is called.
      inOrder.verify(calcService).subtract(20.0,10.0);
      inOrder.verify(calcService).add(20.0,10.0);

   }
}

Step 4 − Execute test cases 
Create a java class file named TestRunner in C:\> Mockito_WORKSPACE to execute Test case(s).
File: TestRunner.java
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

public class TestRunner {
   public static void main(String[] args) {
      Result result = JUnitCore.runClasses(MathApplicationTester.class);
      
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      
      System.out.println(result.wasSuccessful());
   }
}  	
Step 5 − Verify the Result
Compile the classes using javac compiler as follows −
C:\Mockito_WORKSPACE>javac CalculatorService.java MathApplication.
   java MathApplicationTester.java TestRunner.java

Now run the Test Runner to see the result −
C:\Mockito_WORKSPACE>java TestRunner

Verify the output.
testAddAndSubtract(MathApplicationTester): 
Verification in order failure
Wanted but not invoked:
calculatorService.add(20.0, 10.0);
-> at MathApplicationTester.testAddAndSubtract(MathApplicationTester.java:48)
Wanted anywhere AFTER following interaction:
calculatorService.subtract(20.0, 10.0);
-> at MathApplication.subtract(MathApplication.java:13)
false


    31 Lectures 
     43 mins

 Abhinav Manchanda
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