package main.mymath; import java.util.InputMismatchException; import java.util.Scanner; public class MyCalculator { //Addition public void add(int num1,int1 num2) { int result; result = num1 + num2; if(result > Integer.MAX_VALUE || result < Integer.MIN_VALUE){ throw new IllegalArgumentException("输入数字导致溢出"); }else { System.out.println(result); } } //Multiplication public void subtraction(double num1,double num2) { System.out.println(num1 - num2); } //Division public void divide(double num1,double num2) { if(num2==0) { throw new IllegalArgumentException("分母不能为零"); }else { System.out.println(num1 / num2); } } public void calc() { Scanner sc = new Scanner(System.in); System.out.println("premier nombre："); int num1 = sc.nextInt(); System.out.println("deuxieme nombre："); int num2 = sc.nextInt(); System.out.println("choix【+，-，/】"); char op = sc.next().charAt(0); switch (op) { case '+': add(num1, num2); break; case '-': subtraction(num1, num2); break; case '/': divide(num1, num2); break; default: System.out.println("erreur！"); break; } } public static void main(String[] args) { MyCalculator c = new MyCalculator(); c.calc(); } }

好的，根据你提供的代码，以下是一个可能的测试类示例：

package test.mymath;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThrows;
import java.io.ByteArrayInputStream;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;
import java.util.Scanner;
import org.junit.Before;
import org.junit.Test;
import main.mymath.MyCalculator;

public class MyCalculatorTest {

    private MyCalculator calculator;

    @Before
    public void setUp() {
        calculator = new MyCalculator();
    }

    @Test
    public void testAdd() {
        assertEquals(5, calculator.add(2, 3));
        assertEquals(-1, calculator.add(2, -3));
        assertEquals(0, calculator.add(0, 0));
        assertThrows(IllegalArgumentException.class, () -> calculator.add(Integer.MAX_VALUE, 1));
    }

    @Test
    public void testSubtraction() {
        assertEquals(2.0, calculator.subtraction(5.0, 3.0), 0.0);
        assertEquals(-2.0, calculator.subtraction(-5.0, -3.0), 0.0);
        assertEquals(0.0, calculator.subtraction(0.0, 0.0), 0.0);
        assertEquals(0.1, calculator.subtraction(0.3, 0.2), 0.0);
    }

    @Test
    public void testDivide() {
        assertEquals(2.0, calculator.divide(6.0, 3.0), 0.0);
        assertEquals(-2.0, calculator.divide(6.0, -3.0), 0.0);
        assertEquals(0.0, calculator.divide(0.0, 1.0), 0.0);
        assertThrows(IllegalArgumentException.class, () -> calculator.divide(6.0, 0.0));
    }

    @Test
    public void testCalc() {
        String input = "2\n3\n+\n";
        System.setIn(new ByteArrayInputStream(input.getBytes()));
        Scanner scanner = new Scanner(System.in);
        calculator.calc(scanner);
        assertEquals("5\n", systemOut().getHistory());

        input = "5.0\n3.0\n-\n";
        System.setIn(new ByteArrayInputStream(input.getBytes()));
        scanner = new Scanner(System.in);
        calculator.calc(scanner);
        assertEquals("2.0\n", systemOut().getHistory());

        input = "4.0\n2.0\n/\n";
        System.setIn(new ByteArrayInputStream(input.getBytes()));
        scanner = new Scanner(System.in);
        calculator.calc(scanner);
        assertEquals("2.0\n", systemOut().getHistory());
    }

    @Test
    public void testCalcInvalidInput() {
        String input = "invalid\ninput\n";
        System.setIn(new ByteArrayInputStream(input.getBytes()));
        Scanner scanner = new Scanner(System.in);
        assertThrows(NoSuchElementException.class, () -> calculator.calc(scanner));
    }

    private SystemOut systemOut() {
        return new SystemOut();
    }

    private static class SystemOut extends java.io.ByteArrayOutputStream {
        public String getHistory() {
            return new String(this.toByteArray());
        }
    }
}

在上面的测试类示例中，我们使用JUnit框架来测试MyCalculator类的三个方法：add()，subtraction()和divide()，并使用标准输入输出模拟用户交互，测试calc()方法是否能够正确的计算加、减、除三种运算。同时，我们还测试了一些输入无效数据的情况，来保证程序的健壮性。