DeferredResult的Spring MVC单元测试不调用超时回调

import org.junit.jupiter.api.Test;
import org.springframework.test.web.servlet.MockMvc;
import import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.async.DeferredResult;

@RestController
public class MyController {

    @GetMapping("/async")
    public DeferredResult<String> asyncMethod() {
        DeferredResult<String> deferredResult = new DeferredResult<>();
        // 在后台线程中处理请求
        new Thread(() -> {
            // 模拟耗时操作
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            deferredResult.setResult("Hello, World!");
        }).start();
        return deferredResult;
    }
}

public class MyControllerTest {

    @Test
    public void testAsyncMethod() throws Exception {
        MyController controller = new MyController();
        MockMvc mockMvc = MockMvcBuilders.standaloneSetup(controller).build();

        mockMvc.perform(MockMvcRequestBuilders.get("/async"))
                .andExpect(MockMvcResultMatchers.request().asyncStarted())
                .andExpect(MockMvcResultMatchers.request().asyncResult("Hello, World!"))
                .andReturn();
    }
}