如何为包含System.in输入的Switch语句编写单元测试

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import java.io.*;
import java.util.Scanner;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class ExampleServiceTest {

    private final InputStream originalSystemIn = System.in;
    private final PrintStream originalSystemOut = System.out;
    private ByteArrayInputStream testIn;
    private ByteArrayOutputStream testOut;

    @BeforeEach
    public void setUp() {
        testOut = new ByteArrayOutputStream();
        System.setOut(new PrintStream(testOut));
    }

    @AfterEach
    public void restoreStreams() {
        System.setIn(originalSystemIn);
        System.setOut(originalSystemOut);
    }

    @Test
    public void testMethodWithSystemIn() {
        // 模拟输入 "1\n"
        String input = "1\n";
        testIn = new ByteArrayInputStream(input.getBytes());
        System.setIn(testIn);

        // 创建被测试类的实例
        ExampleService service = new ExampleService();

        // 调用被测试的方法
        service.methodWithSystemIn();

        // 验证输出（如果需要）
        String expectedOutput = "You selected option 1.\n";
        assertEquals(expectedOutput, testOut.toString());
    }
}

class ExampleService {
    public void methodWithSystemIn() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter an option: ");
        String option = scanner.nextLine();

        switch (option) {
            case "1":
                System.out.println("You selected option 1.");
                break;
            case "2":
                System.out.println("You selected option 2.");
                break;
            default:
                System.out.println("Invalid option.");
        }
    }
}