--Junit unit tests (b)

1、 Junit使用实例

1) use Junit and assertions way to achieve simple calculator.
Procedure:
(1) create a new project, introducing Junit class package: Test_Of_Junit-> the Build path-> the Add Library-> Junit
(2) Add a class calculator (calcuate)

public class Calculate {
//  加法运算
    public int add(int a,int b) {
        return a+b;
    }
//  减法运算
    public int subtract(int a,int b) {
        return a-b;
    }
//  乘法运算
    public int multiply(int a,int b) {
        return a*b;
    }    

//  除法运算
    public int divide(int a,int b)
    {
        if(b==0) {
            System.out.println("除数不能为0");
            return 0;
        }   
        else
            return a/b;
    }
}

2) Create a Junit test class
(1) Create a Junit Test Case, as follows

import org.junit.Assert;
import org.junit.jupiter.api.Test;

@SuppressWarnings("deprecation")
public class Test_case_of_Calculate {
  @SuppressWarnings("deprecation")
  @Test
  void testAdd() {
      Calculate  test = new Calculate();
      int result = test.add(3, 5);
      Assert.assertEquals("加法有问题",8,result);
  }
  
  @Test
  void testSubtract() {
      Calculate test = new Calculate();
      int result = test.subtract(12, 7);
      Assert.assertEquals("减法有问题", 5,result);//注意，如果出现横线，说明导入包不正确
  }
  
  @Test
  void testMultiply() {
      Calculate test = new Calculate();
      int result = test.multiply(5, 8);
      Assert.assertEquals("乘法有问题", 40,result);
  }

  
  @Test
  void testDevide() {
      Calculate test = new Calculate();
      int result = test.divide(60, 4);
      Assert.assertEquals("除法有问题", 12, result);
  }
}

3) using parameterized classes implement calculator Calculate test

import java.util.Arrays;
import java.util.Collection;
import org.junit.Assert;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource; 

class Test_case1_of_Calculate {
    @BeforeEach
    public static void BeforeEach() {
        System.out.println("***********进行测试***********");
    }

    @AfterAll
    public static void AfterEach() {
        System.out.println("***********测试结束***********");
    }

    @ParameterizedTest // 使用参数化运行
    @MethodSource("test_way1") // 说明使用哪个方法用于参数化
    @DisplayName("加法运算")
    @Test
    public void addTest(int x, int y, int z, String name) {
        System.out.println("----------Test01----------" + name);
        Calculate test = new Calculate();
        int result = test.add(x, y);
        Assert.assertEquals("加法有问题", z, result);
    }
    @ParameterizedTest // 使用参数化运行
    @MethodSource("test_way2") // 说明使用哪个方法用于参数化
    @DisplayName("减法运算")
    @Test
    public void subtractTest(int x, int y, int z, String name) {
        System.out.println("----------Test02----------" + name);
        Calculate test = new Calculate();
        int result = test.subtract(x, y);
        Assert.assertEquals("减法法有问题", z, result);
    }
    @ParameterizedTest // 使用参数化运行
    @MethodSource("test_way3") // 说明使用哪个方法用于参数化
    @DisplayName("乘法运算")
    @Test
    public void multiplyTest(int x, int y, int z, String name) {
        System.out.println("----------Test03----------" + name);
        Calculate  test = new Calculate();
        int result = test.multiply(x, y);
        Assert.assertEquals("乘法法有问题", z, result);
    }

    @ParameterizedTest // 使用参数化运行
    @MethodSource("test_way4") // 说明使用哪个方法用于参数化
    @DisplayName("除法运算")
    @Test
    public void devideTest(int x, int y, int z, String name) {
        System.out.println("----------Test04----------" + name);
        Calculate test = new Calculate();
        int result = test.divide(x, y);
        Assert.assertEquals("除法有问题", z, result);
    }


    public static Collection<Object[]>test_way1() {// Collection集合类型，Object对象数组
        return Arrays.asList(new Object[][] { { 3, 5, 9, "加法运算" }, { 4, 6, 10, "加法运算" } });
    }

    public static Collection<Object[]>test_way2() {// Collection集合类型，Object对象数组
        return Arrays.asList(new Object[][] { { 9, 5, 4, "减法运算" }, { 24, 6, 10, "减法运算" } });
    }

 
    public static Collection<Object[]>test_way3() {// Collection集合类型，Object对象数组
        return Arrays.asList(new Object[][] { { 3, 5, 15, "乘法运算" }, { 4, 6, 18, "乘法运算" } });
    }

    public static Collection<Object[]>test_way4() {// Collection集合类型，Object对象数组
        return Arrays.asList(new Object[][] { { 8, 5, 2, "除法运算" }, { 4, 1, 4, "除法运算" } });
    } 
}