EasyMock - Gestione delle eccezioni

EasyMock fornisce la capacità di un mock di generare eccezioni, quindi la gestione delle eccezioni può essere testata. Dai un'occhiata al seguente frammento di codice.

//add the behavior to throw exception

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

Qui abbiamo aggiunto una clausola di eccezione a un oggetto fittizio. MathApplication fa uso di calcService utilizzando il suo metodo add e il mock lancia una RuntimeException ogni volta che viene richiamato il metodo calcService.add ().

Esempio

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

Testiamo la classe MathApplication, inserendovi una simulazione di calculatorService. Mock sarà creato da EasyMock.

File: 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

Crea un file di classe java denominato TestRunner in C:\> EasyMock_WORKSPACE per eseguire uno o più casi di test.

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

Compila le classi usando javac compilatore come segue:

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

Ora esegui il Test Runner per vedere il risultato:

C:\EasyMock_WORKSPACE>java TestRunner

Verifica l'output.

true