Migrate tests to JUnit 5

Resolves: #1033

samples/boot/webflux/spring-session-sample-boot-webflux.gradle

@@ -9,6 +9,8 @@ dependencies {
 	compile 'org.webjars:bootstrap'
 
 	testCompile "org.springframework.boot:spring-boot-starter-test"
+	testCompile "org.junit.jupiter:junit-jupiter-api"
+	testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine"
 
 	integrationTestCompile seleniumDependencies
 	integrationTestCompile "org.testcontainers:testcontainers"

samples/boot/webflux/src/integration-test/java/sample/AttributeTests.java

@@ -18,10 +18,10 @@ package sample;
 
 import java.util.List;
 
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 import org.openqa.selenium.WebDriver;
 import org.openqa.selenium.htmlunit.HtmlUnitDriver;
 import org.testcontainers.containers.GenericContainer;
@@ -34,7 +34,7 @@ import org.springframework.boot.test.context.TestConfiguration;
 import org.springframework.boot.web.server.LocalServerPort;
 import org.springframework.context.annotation.Bean;
 import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
-import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -43,7 +43,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Rob Winch
  * @author Vedran Pavic
  */
-@RunWith(SpringRunner.class)
+@ExtendWith(SpringExtension.class)
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
 public class AttributeTests {
 
@@ -54,12 +54,12 @@ public class AttributeTests {
 
 	private WebDriver driver;
 
-	@Before
+	@BeforeEach
 	public void setup() {
 		this.driver = new HtmlUnitDriver();
 	}
 
-	@After
+	@AfterEach
 	public void tearDown() {
 		this.driver.quit();
 	}