EasyMock为mock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.
//添加抛出异常的行为 EasyMock.expect( calc Service.add(10.0,20.0)).和Throw(新的运行时异常("添加操作未实现"));
这里我们为模拟对象添加了一个exception子句. MathApplication使用其add方法使用calcService,并且每当调用calcService.add()方法时,mock都会抛出RuntimeException.
步骤1:创建名为CalculatorService的接口以提供数学函数
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); } }
第3步:测试MathApplication类
让我们通过在其中注入一个模拟的calculatorService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); } }
第4步:执行测试用例
在 C:\> EasyMock_WORKSPACE 中创建一个名为TestRunner的java类文件,以执行测试用例.
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Test Runner查看结果:
C: \ EasyMock_WORKSPACE> java TestRunner
验证输出.
true