如何测试resp.getOutputStream()

import org.junit.Test;
import org.mockito.Mockito;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import static org.junit.Assert.assertEquals;
import static org.mockito.Mockito.when;

public class MyServletTest {

    @Test
    public void testGetOutputStream() throws IOException {
        // 创建模拟的HttpServletRequest和HttpServletResponse对象
        HttpServletRequest request = Mockito.mock(HttpServletRequest.class);
        HttpServletResponse response = Mockito.mock(HttpServletResponse.class);

        // 设置模拟请求的参数和属性
        when(request.getParameter("param")).thenReturn("value");

        // 创建一个ByteArrayOutputStream来捕获写入的数据
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

        // 创建一个模拟的ServletOutputStream对象，将数据写入ByteArrayOutputStream
        ServletOutputStream servletOutputStream = new ServletOutputStream() {
            @Override
            public void write(int b) throws IOException {
                outputStream.write(b);
            }
        };

        // 设置模拟的ServletOutputStream对象为response的输出流
        when(response.getOutputStream()).thenReturn(servletOutputStream);

        // 调用被测试的方法，获取输出流
        ServletClass servlet = new ServletClass();
        servlet.doGet(request, response);

        // 验证输出流是否正常工作，例如判断写入的数据是否正确
        String expectedOutput = "Hello, World!";
        assertEquals(expectedOutput, outputStream.toString());

        // 清理测试环境，关闭输出流
        outputStream.close();
    }
}