[이동욱스프링책]mvc.perform(get("/hello")).andExpect(status().isOk()).andExpect(content().string(hello)); 오류

package com.jojoldu.book.springboot.web;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@RunWith(SpringRunner.class)
@WebMvcTest(controllers = HelloController.class)
public class HelloControllerTest {
    @Autowired
    private MockMvc mvc;

    @Test
    public void hello가_리턴된다() throws Exception{
        String hello = "hello";

        mvc.perform(get("/hello")).andExpect(status().isOk()).andExpect(content().string(hello));
    }
}

1. 밑에 import static 세 줄 추가
2. File - Settings - Build,Execution,Deployment - Gradle에 Run test using 을 IntelliJ로 변경