JUnit集成（ JUnit Integration）

在本章中，我们将学习如何将JUnit和EasyMock集成在一起。 这里我们将创建一个Math Application，它使用CalculatorService来执行基本的数学运算，例如加法，减法，乘法和除法。 我们将使用EasyMock来模拟CalculatorService的虚拟实现。 此外，我们广泛使用注释来展示它们与JUnit和EasyMock的兼容性。

下面以逐步的方式讨论该过程。

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

让我们通过在其中注入一个模拟的calculatorService来测试MathApplication类。 Mock将由EasyMock创建。

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.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

在C:\》 EasyMock_WORKSPACE创建一个名为TestRunner的java类文件，以执行测试用例。

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

使用javac编译器编译类，如下所示:

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

现在运行Test Runner来查看结果:

C:\EasyMock_WORKSPACE>java TestRunner

验证输出。

true

要了解有关JUnit的更多信息，请参阅xnip中的JUnit教程。