Mockito 提供了一个应答接口, 允许 stubbing 具有泛型接口。

语法

//add the behavior to add numberswhen(calcService.add(20.0,10.0)).thenAnswer(newAnswer<Double>(){@OverridepublicDoubleanswer(InvocationOnMockinvocation)throwsThrowable{//get the arguments passed to mockObject[]args =invocation.getArguments();//get the mock Objectmock =invocation.getMock();//return the resultreturn30.0;}});

例如

步骤1−创建一个称为 CalculatorService 的接口, 以提供数学函数

文件: CalculatorService. java

/**
 * 计算相关服务
 */
public interface CalculatorService {
    /**
     * 加法
     *
     * @param input1
     * @param input2
     * @return
     */
    public double add(double input1, double input2);

    /**
     * 减法
     *
     * @param input1
     * @param input2
     * @return
     */
    public double subtract(double input1, double input2);

    /**
     * 乘法
     *
     * @param input1
     * @param input2
     * @return
     */
    public double multiply(double input1, double input2);

    /**
     * 除法
     *
     * @param input1
     * @param input2
     * @return
     */
    public double divide(double input1, double input2);
}

步骤2−创建一个 JAVA 类来表示 MathApplication

文件: MathApplication. java

/**
 * 数学应用
 */
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

让我们测试 MathApplication 类, 通过注入一个 calculatorService 的Mock。Mock将由 Mockito 创建。

在这里, 我们添加了一个模拟方法调用, add() 到模拟对象when ()。但是在测试过程中, 我们在调用 add () 之前调用了subtract ()。当我们使用 Mockito createStrictMock () 创建一个模拟对象时, 该方法的执行顺序很重要。

文件: MathApplicationTester. java

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.runners.MockitoJUnitRunner;
import org.mockito.stubbing.Answer;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(MockitoJUnitRunner.class)
public class MathApplicationTester {

    private MathApplication mathApplication;
    private CalculatorService calcService;

    @Before
    public void setUp(){
        mathApplication = new MathApplication();
        calcService = mock(CalculatorService.class);
        mathApplication.setCalculatorService(calcService);
    }

    @Test
    public void testAdd(){

        //add the behavior to add numbers
        when(calcService.add(20.0,10.0)).thenAnswer(new Answer<Double>() {

            @Override
            public Double answer(InvocationOnMock invocation) throws Throwable {
                //get the arguments passed to mock
                Object[] args = invocation.getArguments();

                //get the mock
                Object mock = invocation.getMock();

                //return the result
                return 30.0;
            }
        });

        //test the add functionality
        Assert.assertEquals(mathApplication.add(20.0, 10.0),30.0,0);
    }
}

步骤4−执行测试用例

在C: \ > Mockito_WORKSPACE中创建名为 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());
    }
}

步骤5−验证结果

使用javac编译器编译类, 如下所示−

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

现在运行TestRunner以查看结果−

C:\Mockito_WORKSPACE>java TestRunner

验证输出。

true

翻译自：https://www.tutorialspoint.com/mockito/mockito_callbacks.htm