Validate our own tests work with JUnit5 and the vintage engine

Closes gh-14737

Co-authored-by: Stephane Nicoll <snicoll@pivotal.io>

spring-boot-samples/spring-boot-sample-web-ui/src/test/java/sample/web/ui/MessageControllerWebTests.java

@@ -20,13 +20,11 @@ import java.util.regex.Pattern;
 
 import org.hamcrest.Description;
 import org.hamcrest.TypeSafeMatcher;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.test.context.junit4.SpringRunner;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.context.WebApplicationContext;
@@ -44,35 +42,34 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  * @author Biju Kunjummen
  * @author Doo-Hwan, Kwak
  */
-@RunWith(SpringRunner.class)
 @SpringBootTest
-public class MessageControllerWebTests {
+class MessageControllerWebTests {
 
 	@Autowired
 	private WebApplicationContext wac;
 
 	private MockMvc mockMvc;
 
-	@Before
+	@BeforeEach
 	public void setup() {
 		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build();
 	}
 
 	@Test
-	public void testHome() throws Exception {
+	void testHome() throws Exception {
 		this.mockMvc.perform(get("/")).andExpect(status().isOk())
 				.andExpect(content().string(containsString("<title>Messages")));
 	}
 
 	@Test
-	public void testCreate() throws Exception {
+	void testCreate() throws Exception {
 		this.mockMvc.perform(post("/").param("text", "FOO text").param("summary", "FOO"))
 				.andExpect(status().isFound())
 				.andExpect(header().string("location", RegexMatcher.matches("/[0-9]+")));
 	}
 
 	@Test
-	public void testCreateValidation() throws Exception {
+	void testCreateValidation() throws Exception {
 		this.mockMvc.perform(post("/").param("text", "").param("summary", ""))
 				.andExpect(status().isOk())
 				.andExpect(content().string(containsString("is required")));

spring-boot-samples/spring-boot-sample-web-ui/src/test/java/sample/web/ui/SampleWebUiApplicationTests.java

@@ -18,8 +18,7 @@ package sample.web.ui;
 
 import java.net.URI;
 
-import org.junit.Test;
-import org.junit.runner.RunWith;
+import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -28,7 +27,6 @@ import org.springframework.boot.test.web.client.TestRestTemplate;
 import org.springframework.boot.web.server.LocalServerPort;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
-import org.springframework.test.context.junit4.SpringRunner;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 
@@ -39,9 +37,8 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Dave Syer
  */
-@RunWith(SpringRunner.class)
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
-public class SampleWebUiApplicationTests {
+class SampleWebUiApplicationTests {
 
 	@Autowired
 	private TestRestTemplate restTemplate;
@@ -50,7 +47,7 @@ public class SampleWebUiApplicationTests {
 	private int port;
 
 	@Test
-	public void testHome() {
+	void testHome() {
 		ResponseEntity<String> entity = this.restTemplate.getForEntity("/", String.class);
 		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
 		assertThat(entity.getBody()).contains("<title>Messages");
@@ -58,7 +55,7 @@ public class SampleWebUiApplicationTests {
 	}
 
 	@Test
-	public void testCreate() {
+	void testCreate() {
 		MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
 		map.set("text", "FOO text");
 		map.set("summary", "FOO");
@@ -67,7 +64,7 @@ public class SampleWebUiApplicationTests {
 	}
 
 	@Test
-	public void testCss() {
+	void testCss() {
 		ResponseEntity<String> entity = this.restTemplate.getForEntity(
 				"http://localhost:" + this.port + "/css/bootstrap.min.css", String.class);
 		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);