diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketExtension.java b/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketExtension.java
index 4466ab3c391..c8a62ccabe7 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketExtension.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketExtension.java
@@ -30,8 +30,9 @@ import org.springframework.util.LinkedCaseInsensitiveMap;
 import org.springframework.util.StringUtils;
 
 /**
- * Represents a WebSocket extension as defined in the RFC 6455.
- * WebSocket extensions add protocol features to the WebSocket protocol. The extensions
+ * Represents a WebSocket extension as defined in RFC 6455.
+ *
+ * <p>WebSocket extensions add protocol features to the WebSocket protocol. The extensions
  * used within a session are negotiated during the handshake phase as follows:
  * <ul>
  * <li>the client may ask for specific extensions in the HTTP handshake request</li>
@@ -39,10 +40,10 @@ import org.springframework.util.StringUtils;
  * </ul>
  *
  * <p>WebSocket Extension HTTP headers may include parameters and follow
- * <a href="https://tools.ietf.org/html/rfc7230#section-3.2">RFC 7230 section 3.2</a></p>
+ * <a href="https://tools.ietf.org/html/rfc7230#section-3.2">RFC 7230 section 3.2</a>
  *
- * <p>Note that the order of extensions in HTTP headers defines their order of execution,
- * for example, extensions "foo, bar" will be executed as "bar(foo(message))".</p>
+ * <p>Note that the order of extensions in HTTP headers defines their order of execution &mdash;
+ * for example, extensions "foo, bar" will be executed as "bar(foo(message))".
  *
  * @author Brian Clozel
  * @author Juergen Hoeller
diff --git a/spring-websocket/src/test/java/org/springframework/web/socket/WebSocketExtensionTests.java b/spring-websocket/src/test/java/org/springframework/web/socket/WebSocketExtensionTests.java
index e30b636119c..6dbaeaac167 100644
--- a/spring-websocket/src/test/java/org/springframework/web/socket/WebSocketExtensionTests.java
+++ b/spring-websocket/src/test/java/org/springframework/web/socket/WebSocketExtensionTests.java
@@ -21,6 +21,7 @@ import java.util.List;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
 
 /**
  * Test fixture for {@link WebSocketExtension}.
@@ -34,13 +35,11 @@ class WebSocketExtensionTests {
 		List<WebSocketExtension> extensions =
 				WebSocketExtension.parseExtensions("x-test-extension ; foo=bar ; bar=baz");
 
-		assertThat(extensions).hasSize(1);
-		WebSocketExtension extension = extensions.get(0);
-
-		assertThat(extension.getName()).isEqualTo("x-test-extension");
-		assertThat(extension.getParameters()).hasSize(2);
-		assertThat(extension.getParameters().get("foo")).isEqualTo("bar");
-		assertThat(extension.getParameters().get("bar")).isEqualTo("baz");
+		assertThat(extensions).singleElement().satisfies(extension -> {
+			assertThat(extension.getName()).isEqualTo("x-test-extension");
+			assertThat(extension.getParameters())
+					.containsOnly(entry("foo", "bar"), entry("bar", "baz"));
+		});
 	}
 
 	@Test
@@ -48,7 +47,7 @@ class WebSocketExtensionTests {
 		List<WebSocketExtension> extensions =
 				WebSocketExtension.parseExtensions("x-foo-extension, x-bar-extension");
 
-		assertThat(extensions.stream().map(WebSocketExtension::getName))
+		assertThat(extensions).extracting(WebSocketExtension::getName)
 				.containsExactly("x-foo-extension", "x-bar-extension");
 	}