EasyMock - 异常处理

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EasyMock 为模拟提供了抛出异常的功能，因此可以测试异常处理。看一下下面的代码片段。

//add the behavior to throw exception

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

这里我们向模拟对象添加了一个异常子句。MathApplication 通过其 add 方法来使用 calcService，并且每当调用 calcService.add() 方法时，模拟都会抛出 RuntimeException。

例子

步骤1：创建一个名为CalculatorService的接口来提供数学函数

文件：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);
}

第2步：创建一个JAVA类来表示MathApplication

文件：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);
   }
}

步骤 3：测试 MathApplication 类

让我们通过向其中注入calculatorService 的模拟来测试MathApplication 类。模拟将由 EasyMock 创建。

文件：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);
   }
}

步骤 4：执行测试用例

在C:\> EasyMock_WORKSPACE中创建一个名为 TestRunner 的 java 类文件来执行测试用例。

文件：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());
   }
}

第 5 步：验证结果

使用javac编译器编译类，如下所示 -

C:\EasyMock_WORKSPACE>javac MathApplicationTester.java

现在运行测试运行程序来查看结果 -

C:\EasyMock_WORKSPACE>java TestRunner

输出

验证输出。

true