在 IDEA 中 使用 JUnit4

環境

• Java 版本：1.8.0_172
• IDEA 版本：ideaIU-2017.3.5

情景代碼

/**
 * Created by Administrator on 2018/6/16 12:00 in Beijing.
 */

public class Calculator {
    public int add(int a, int b) {
        return a + b ;
    }

    public int sub(int a, int b) {
        return a - b ;
    }

    public int mul(int a, int b) {
        return a * b ;
    }

    public int div(int a, int b) {
        if(b == 0) {
            throw new ArithmeticException("除數不能爲零") ;
        }

        return a / b ;
    }

}

使用過程

右鍵相應的類，Go To --> Test，彈出以下框

點擊OK後，IDEA 將自動 幫咱們 建立好 測試代碼。

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

/**
 * Created by Administrator on 2018/6/16 21:29 in Beijing.
 */

public class CalculatorTest {

    @Before
    public void setUp() throws Exception {
    }

    @After
    public void tearDown() throws Exception {
    }

    @Test
    public void add() {
    }

    @Test
    public void sub() {
    }

    @Test
    public void mul() {
    }

    @Test
    public void div() {
    }
}

最終的測試代碼以下，

import org.junit.*;

import static org.junit.Assert.*;

/**
 * Created by Administrator on 2018/6/16 21:29 in Beijing.
 */

public class CalculatorTest {

    @BeforeClass
    public static void beforeClass() {
        System.out.println("Before Class");
    }

    @AfterClass
    public static void afterClass() {
        System.out.println("After Class");
    }

    @Before
    public void setUp() throws Exception {
        System.out.println("Before Method");
    }

    @After
    public void tearDown() throws Exception {
        System.out.println("After Method");
    }

    @Test
    public void add() {
        System.out.println("add");
        int a = 20 ;
        int b = 10 ;
        Calculator cal = new Calculator() ;
        int result = cal.add(20, 10) ;

        Assert.assertEquals(a + b, result) ;
    }

    @Test
    public void sub() {
        System.out.println("sub");
        int a = 20 ;
        int b = 10 ;
        Calculator cal = new Calculator() ;
        int result = cal.sub(20, 10) ;

        Assert.assertEquals(a - b, result) ;
    }

    @Test
    public void mul1() {
        System.out.println("mul1");
        int a = 20 ;
        int b = 10 ;
        Calculator cal = new Calculator() ;
        int result = cal.mul(20, 10) ;

        Assert.assertEquals(a * b, result) ;
    }

    @Test
    @Ignore
    public void mul2() {
        System.out.println("mul2");
        int a = 20 ;
        int b = 10 ;
        Calculator cal = new Calculator() ;
        int result = cal.mul(20, 10) ;

        Assert.assertEquals(a * b, result) ;
    }

    @Test
    public void div1() {
        System.out.println("div1");
        int a = 20 ;
        int b = 10 ;
        Calculator cal = new Calculator() ;
        int result = cal.div(20, 10) ;

        Assert.assertEquals(a / b, result) ;
    }

    @Test(expected = ArithmeticException.class)
    public void div2() {
        System.out.println("div2");
        int a = 20 ;
        int b = 0 ;
        Calculator cal = new Calculator() ;
        int result = cal.div(20, 10) ;

        Assert.assertEquals(a / b, result) ;
    }
}

最後點擊Run方法， 輸出以下， 大功告成。