Update the samples to make use of auto-configured TestRestTemplate

Closes gh-6730

spring-boot-samples/spring-boot-sample-servlet/src/test/java/sample/servlet/SampleServletApplicationTests.java

@@ -21,7 +21,6 @@ import org.junit.runner.RunWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.security.SecurityProperties;
-import org.springframework.boot.context.embedded.LocalServerPort;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.boot.test.web.client.TestRestTemplate;
@@ -42,23 +41,22 @@ import static org.assertj.core.api.Assertions.assertThat;
 @DirtiesContext
 public class SampleServletApplicationTests {
 
-	@LocalServerPort
-	private int port;
+	@Autowired
+	private TestRestTemplate restTemplate;
 
 	@Autowired
 	private SecurityProperties security;
 
 	@Test
 	public void testHomeIsSecure() throws Exception {
-		ResponseEntity<String> entity = new TestRestTemplate()
-				.getForEntity("http://localhost:" + this.port, String.class);
+		ResponseEntity<String> entity = this.restTemplate.getForEntity("/", String.class);
 		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.UNAUTHORIZED);
 	}
 
 	@Test
 	public void testHome() throws Exception {
-		ResponseEntity<String> entity = new TestRestTemplate("user", getPassword())
-				.getForEntity("http://localhost:" + this.port, String.class);
+		ResponseEntity<String> entity = this.restTemplate
+				.withBasicAuth("user", getPassword()).getForEntity("/", String.class);
 		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
 		assertThat(entity.getBody()).isEqualTo("Hello World");
 	}