四则运算器

在Eclipse中配置Junit的方法：

 

1、 在要使用Junit的project名上，点击properties--java build path-libraries, 点击Add library（如图四）,选择Junit即可。点击Add library，在弹出的对话框中选择Jnuit（如图五），接下来选择junit版本（如图六）即可。

图四

 

图五

图六

四则运算的方法（加减乘除）

package cn.hnzj.jy212;

public class Calculator {

    public int add(int a,int b) {

           return a+b;

    }

    public int minus(int a,int b) {

           return a-b;

    }

    public int multiply(int a,int b) {

           return a*b;

    }

    public int divide(int a,int b) {

           return a/b;

    }

}

Junit测试类：

package cn.hnzj.jy212;

import static org.junit.Assert.*;

import org.junit.Before;

import org.junit.Test;

 

public class CalculatorTest {

       @Before

       public void setUp() throws Exception {

       }

       @Test

       public void testAdd() {

              //实例化一个对象

              Calculator c = new Calculator();

              //对象调用被侧方法及传参

              int result = c.add(2, 5);

              //使用断言比较预期结果和实际结果

              assertEquals(7,result,0.0);

              //Assert.assertEquals(7, result);

              //fail("Not yet implemented");

       }

       @Test

       public void testMinus() {

              //fail("Not yet implemented");

              Calculator c = new Calculator();

              int result = c.minus(2, 5);

              assertEquals(-3,result,0.0);

       }

       @Test

       public void testMultiply() {

              //fail("Not yet implemented");

              Calculator c = new Calculator();

              int result = c.multiply(2, 5);

              assertEquals(10,result,0.0);

       }

       @Test

       public void testDivide() {

              //fail("Not yet implemented");

              Calculator c = new Calculator();

              int result = c.divide(10, 5);

              assertEquals(2,result);

       }

}

 

结果截图：