Why is my controller test not working even though it mimics a working example from javadevjournal?

Question

I am following the below article to test my contoller on its own without having to start a spring application completely. Please can you let me know where I am going wrong, is the article wrong?

https://www.javadevjournal.com/spring-boot/testing-in-spring-boot/

The error I get is as below

java.lang.IllegalStateException: Unable to find a @SpringBootConfiguration, you need to use @ContextConfiguration or @SpringBootTest(classes=...) with your test

SearchController.java

@RestController
@RequestMapping(value = "/top5")
public class SearchController {
    @Autowired
    private UserService userService;

    @RequestMapping(value = "/{user}", method = RequestMethod.GET)
    public List<Repo> getInfo(@PathVariable(name = "user") String user) {
        System.out.println("Querying for [" + user + "]");
        return userService.getResults(user);
    }
}

UserService.java

@Service
public class UserService {
    private static final String search_url = "https://api.github.com/users/%s/repos?page=1&per_page=5";

    @Autowired
    RestTemplate rt;

    public List<Repo> getResults(String user) {
        System.out.println("Invoking: " + String.format(search_url, user));
        Repo[] a = rt.getForEntity(String.format(search_url, user), Repo[].class).getBody();
        return Arrays.asList(a);
    }
}

SearchControllerTest.java

@RunWith(SpringRunner.class)
@WebMvcTest(value = SearchController.class)
public class SearchControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @MockBean
    private UserService userService;

    private static List<Repo> repoList;

    @BeforeClass
    public static void setupTestData() {
        repoList = new ArrayList<Repo>();
        // Populate with test data
        repoList.add(new Repo("1", "Repo1", "Repository 1", "http://myurl.com/1", "Description 1"));
        repoList.add(new Repo("2", "Repo2", "Repository 2", "http://myurl.com/2", "Description 2"));
        repoList.add(new Repo("3", "Repo3", "Repository 3", "http://myurl.com/3", "Description 3"));
        repoList.add(new Repo("4", "Repo4", "Repository 4", "http://myurl.com/4", "Description 4"));
        repoList.add(new Repo("5", "Repo5", "Repository 5", "http://myurl.com/5", "Description 5"));
    }

    @Test
    public void testGetInfo() throws Exception {
        String apiUrl = "/top5/tester";
        // Setup "Mockito" to mock userService call
        Mockito.when(userService.getResults(Mockito.anyString())).thenReturn(repoList);

        // Build a GET Request and send it to the test server
        RequestBuilder rb = MockMvcRequestBuilders.get(apiUrl).accept(MediaType.APPLICATION_JSON);
        MvcResult r = mockMvc.perform(rb).andReturn(); // throws Exception

        // Validate response
        String tr = r.getResponse().getContentAsString();
        // System.out.println(tr);

        String er = "[{\"id\":\"1\",\"name\":\"Repo1\",\"full_name\":\"Repository 1\",\"html_url\":\"http://myurl.com/1\",\"description\":\"Description 1\"},{\"id\":\"2\",\"name\":\"Repo2\",\"full_name\":\"Repository 2\",\"html_url\":\"http://myurl.com/2\",\"description\":\"Description 2\"},{\"id\":\"3\",\"name\":\"Repo3\",\"full_name\":\"Repository 3\",\"html_url\":\"http://myurl.com/3\",\"description\":\"Description 3\"},{\"id\":\"4\",\"name\":\"Repo4\",\"full_name\":\"Repository 4\",\"html_url\":\"http://myurl.com/4\",\"description\":\"Description 4\"},{\"id\":\"5\",\"name\":\"Repo5\",\"full_name\":\"Repository 5\",\"html_url\":\"http://myurl.com/5\",\"description\":\"Description 5\"}]";
        JSONAssert.assertEquals(er, tr, true);

        // Or we can use JUnit's assertEquals() method
        // assertEquals("REST API Returned incorrect response.", er, tr);
    }
}

Repo.class

public class Repo {

    private String id;
    private String name;
    private String description;

    private String fullName;

    private String htmlUrl;

    public Repo(String id, String name, String description, String fullName, String htmlUrl) {
        this.id = id;
        this.name = name;
        this.description = description;
        this.fullName = fullName;
        this.htmlUrl = htmlUrl;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getDescription() {
        return description;
    }

    public String getFullName() {
        return fullName;
    }

    public String getHtmlUrl() {
        return htmlUrl;
    }
}