diff --git a/samples/default-authorizationserver/samples-default-authorizationserver.gradle b/samples/default-authorizationserver/samples-default-authorizationserver.gradle
index 3dea316f..e84b55ea 100644
--- a/samples/default-authorizationserver/samples-default-authorizationserver.gradle
+++ b/samples/default-authorizationserver/samples-default-authorizationserver.gradle
@@ -25,3 +25,7 @@ dependencies {
 	testImplementation "org.junit.jupiter:junit-jupiter"
 	testImplementation "net.sourceforge.htmlunit:htmlunit"
 }
+
+tasks.named("test") {
+	useJUnitPlatform()
+}
diff --git a/samples/demo-authorizationserver/samples-demo-authorizationserver.gradle b/samples/demo-authorizationserver/samples-demo-authorizationserver.gradle
index f7eac0a7..34dc9405 100644
--- a/samples/demo-authorizationserver/samples-demo-authorizationserver.gradle
+++ b/samples/demo-authorizationserver/samples-demo-authorizationserver.gradle
@@ -30,3 +30,7 @@ dependencies {
 	testImplementation "org.junit.jupiter:junit-jupiter"
 	testImplementation "net.sourceforge.htmlunit:htmlunit"
 }
+
+tasks.named("test") {
+	useJUnitPlatform()
+}
diff --git a/samples/demo-authorizationserver/src/test/java/sample/DemoAuthorizationServerApplicationTests.java b/samples/demo-authorizationserver/src/test/java/sample/DemoAuthorizationServerApplicationTests.java
index 92a3bc5c..36d121f0 100644
--- a/samples/demo-authorizationserver/src/test/java/sample/DemoAuthorizationServerApplicationTests.java
+++ b/samples/demo-authorizationserver/src/test/java/sample/DemoAuthorizationServerApplicationTests.java
@@ -68,14 +68,15 @@ public class DemoAuthorizationServerApplicationTests {
 	}
 
 	@Test
-	public void whenLoginSuccessfulThenDisplayNotFoundError() throws IOException {
+	public void whenLoginSuccessfulThenDisplayBadRequestError() throws IOException {
 		HtmlPage page = this.webClient.getPage("/");
 
 		assertLoginPage(page);
 
 		this.webClient.getOptions().setThrowExceptionOnFailingStatusCode(false);
 		WebResponse signInResponse = signIn(page, "user1", "password").getWebResponse();
-		assertThat(signInResponse.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND.value());	// there is no "default" index page
+
+		assertThat(signInResponse.getStatusCode()).isEqualTo(HttpStatus.BAD_REQUEST.value());	// there is no "default" index page
 	}
 
 	@Test
@@ -86,7 +87,7 @@ public class DemoAuthorizationServerApplicationTests {
 
 		HtmlElement alert = loginErrorPage.querySelector("div[role=\"alert\"]");
 		assertThat(alert).isNotNull();
-		assertThat(alert.getTextContent()).isEqualTo("Bad credentials");
+		assertThat(alert.asNormalizedText()).isEqualTo("Invalid username or password.");
 	}
 
 	@Test