添加行为（ Adding Behavior）

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2023-12-01

EasyMock使用expect()和expectLassCall()方法为模拟对象添加功能。请查看以下代码段。

//add the behavior of calc service to add two numbers
EasyMock.expect(calcService.add(10.0,20.0)).andReturn(30.00);

在这里，我们已经指示EasyMock给出了向calcService的add方法添加10和20的行为，结果返回30.00的值。

在这个时间点，Mock只记录了行为，但它不能作为模拟对象。调用重播后，它按预期工作。

//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);

Example without EasyMock.Replay()

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 the 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: Execute 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 Calculator Service.java Math Application.java Math Application Tester.java Test Runner.java

现在运行Test Runner来查看结果:

C:\EasyMock_WORKSPACE>java TestRunner

验证输出。

testAdd(MathApplicationTester): expected:<0.0> but was:<30.0>
false

Example with EasyMock.Replay()

Step 1: Create an interface called CalculatorService to provide mathematical functions.