diff --git a/spring-web/src/test/java/org/springframework/web/service/invoker/HttpServiceMethodTests.java b/spring-web/src/test/java/org/springframework/web/service/invoker/HttpServiceMethodTests.java
index 00d710a12d..b890ec83ea 100644
--- a/spring-web/src/test/java/org/springframework/web/service/invoker/HttpServiceMethodTests.java
+++ b/spring-web/src/test/java/org/springframework/web/service/invoker/HttpServiceMethodTests.java
@@ -99,7 +99,7 @@ class HttpServiceMethodTests {
 		assertThat(voidEntity.getBody()).isNull();
 
 		List<String> list = service.getList();
-		assertThat(list).containsExactly("exchangeForBody");
+		assertThat(list).containsOnly("exchangeForBody");
 	}
 
 	@Test
@@ -183,7 +183,7 @@ class HttpServiceMethodTests {
 		assertThat(requestValues.getHttpMethod()).isEqualTo(HttpMethod.POST);
 		assertThat(requestValues.getUriTemplate()).isEqualTo("/url");
 		assertThat(requestValues.getHeaders().getContentType()).isEqualTo(MediaType.APPLICATION_JSON);
-		assertThat(requestValues.getHeaders().getAccept()).containsExactly(MediaType.APPLICATION_JSON);
+		assertThat(requestValues.getHeaders().getAccept()).containsOnly(MediaType.APPLICATION_JSON);
 	}
 
 	@Test
@@ -201,7 +201,7 @@ class HttpServiceMethodTests {
 		assertThat(requestValues.getHttpMethod()).isEqualTo(HttpMethod.GET);
 		assertThat(requestValues.getUriTemplate()).isEqualTo("/base");
 		assertThat(requestValues.getHeaders().getContentType()).isEqualTo(MediaType.APPLICATION_CBOR);
-		assertThat(requestValues.getHeaders().getAccept()).containsExactly(MediaType.APPLICATION_CBOR);
+		assertThat(requestValues.getHeaders().getAccept()).containsOnly(MediaType.APPLICATION_CBOR);
 
 		service.performPost();
 
@@ -209,7 +209,7 @@ class HttpServiceMethodTests {
 		assertThat(requestValues.getHttpMethod()).isEqualTo(HttpMethod.POST);
 		assertThat(requestValues.getUriTemplate()).isEqualTo("/base/url");
 		assertThat(requestValues.getHeaders().getContentType()).isEqualTo(MediaType.APPLICATION_JSON);
-		assertThat(requestValues.getHeaders().getAccept()).containsExactly(MediaType.APPLICATION_JSON);
+		assertThat(requestValues.getHeaders().getAccept()).containsOnly(MediaType.APPLICATION_JSON);
 	}
 
 	@Test  // gh-32049
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMappingTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMappingTests.java
index f39d13071b..5c04020d5e 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMappingTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMappingTests.java
@@ -22,7 +22,8 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.lang.reflect.Method;
 import java.security.Principal;
-import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -79,17 +80,16 @@ class RequestMappingHandlerMappingTests {
 	void resolveEmbeddedValuesInPatterns() {
 		this.handlerMapping.setEmbeddedValueResolver(value -> "/${pattern}/bar".equals(value) ? "/foo/bar" : value);
 
-		String[] patterns = new String[] { "/foo", "/${pattern}/bar" };
+		String[] patterns = { "/foo", "/${pattern}/bar" };
 		String[] result = this.handlerMapping.resolveEmbeddedValuesInPatterns(patterns);
 
-		assertThat(result).isEqualTo(new String[] { "/foo", "/foo/bar" });
+		assertThat(result).containsExactly("/foo", "/foo/bar");
 	}
 
 	@Test
 	void pathPrefix() {
 		this.handlerMapping.setEmbeddedValueResolver(value -> "/${prefix}".equals(value) ? "/api" : value);
-		this.handlerMapping.setPathPrefixes(Collections.singletonMap(
-				"/${prefix}", HandlerTypePredicate.forAnnotation(RestController.class)));
+		this.handlerMapping.setPathPrefixes(Map.of("/${prefix}", HandlerTypePredicate.forAnnotation(RestController.class)));
 
 		Method method = ReflectionUtils.findMethod(UserController.class, "getUser");
 		RequestMappingInfo info = this.handlerMapping.getMappingForMethod(method, UserController.class);
@@ -102,8 +102,11 @@ class RequestMappingHandlerMappingTests {
 	void resolveRequestMappingViaComposedAnnotation() {
 		RequestMappingInfo info = assertComposedAnnotationMapping("postJson", "/postJson", RequestMethod.POST);
 
-		assertThat(info.getConsumesCondition().getConsumableMediaTypes().iterator().next().toString()).isEqualTo(MediaType.APPLICATION_JSON_VALUE);
-		assertThat(info.getProducesCondition().getProducibleMediaTypes().iterator().next().toString()).isEqualTo(MediaType.APPLICATION_JSON_VALUE);
+		Set<MediaType> consumableMediaTypes = info.getConsumesCondition().getConsumableMediaTypes();
+		Set<MediaType> producibleMediaTypes = info.getProducesCondition().getProducibleMediaTypes();
+
+		assertThat(consumableMediaTypes).singleElement().hasToString(MediaType.APPLICATION_JSON_VALUE);
+		assertThat(producibleMediaTypes).singleElement().hasToString(MediaType.APPLICATION_JSON_VALUE);
 	}
 
 	@Test // SPR-14988
@@ -111,7 +114,7 @@ class RequestMappingHandlerMappingTests {
 		RequestMappingInfo requestMappingInfo = assertComposedAnnotationMapping(RequestMethod.POST);
 
 		ConsumesRequestCondition condition = requestMappingInfo.getConsumesCondition();
-		assertThat(condition.getConsumableMediaTypes()).isEqualTo(Collections.singleton(MediaType.APPLICATION_XML));
+		assertThat(condition.getConsumableMediaTypes()).containsOnly(MediaType.APPLICATION_XML);
 	}
 
 	@Test // gh-22010
diff --git a/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMappingTests.java b/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMappingTests.java
index bb13f9a5e6..a503886783 100644
--- a/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMappingTests.java
+++ b/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMappingTests.java
@@ -143,7 +143,7 @@ class RequestMappingHandlerMappingTests {
 		mapping.setApplicationContext(wac);
 		mapping.afterPropertiesSet();
 
-		assertThat(extensions).isEqualTo(Collections.singleton("json"));
+		assertThat(extensions).containsOnly("json");
 	}
 
 	@Test
@@ -167,14 +167,12 @@ class RequestMappingHandlerMappingTests {
 
 	@PathPatternsParameterizedTest
 	void resolveEmbeddedValuesInPatterns(RequestMappingHandlerMapping mapping) {
-		mapping.setEmbeddedValueResolver(
-				value -> "/${pattern}/bar".equals(value) ? "/foo/bar" : value
-		);
+		mapping.setEmbeddedValueResolver(value -> "/${pattern}/bar".equals(value) ? "/foo/bar" : value);
 
-		String[] patterns = new String[] { "/foo", "/${pattern}/bar" };
+		String[] patterns = { "/foo", "/${pattern}/bar" };
 		String[] result = mapping.resolveEmbeddedValuesInPatterns(patterns);
 
-		assertThat(result).isEqualTo(new String[] { "/foo", "/foo/bar" });
+		assertThat(result).containsExactly("/foo", "/foo/bar");
 	}
 
 	@PathPatternsParameterizedTest
@@ -188,7 +186,7 @@ class RequestMappingHandlerMappingTests {
 		RequestMappingInfo info = mapping.getMappingForMethod(method, UserController.class);
 
 		assertThat(info).isNotNull();
-		assertThat(info.getPatternValues()).isEqualTo(Collections.singleton("/api/user/{id}"));
+		assertThat(info.getPatternValues()).containsOnly("/api/user/{id}");
 	}
 
 	@PathPatternsParameterizedTest // gh-23907
@@ -226,10 +224,11 @@ class RequestMappingHandlerMappingTests {
 		RequestMappingInfo info = assertComposedAnnotationMapping(
 				mapping, "postJson", "/postJson", RequestMethod.POST);
 
-		assertThat(info.getConsumesCondition().getConsumableMediaTypes().iterator().next().toString())
-				.isEqualTo(MediaType.APPLICATION_JSON_VALUE);
-		assertThat(info.getProducesCondition().getProducibleMediaTypes().iterator().next().toString())
-				.isEqualTo(MediaType.APPLICATION_JSON_VALUE);
+		Set<MediaType> consumableMediaTypes = info.getConsumesCondition().getConsumableMediaTypes();
+		Set<MediaType> producibleMediaTypes = info.getProducesCondition().getProducibleMediaTypes();
+
+		assertThat(consumableMediaTypes).singleElement().hasToString(MediaType.APPLICATION_JSON_VALUE);
+		assertThat(producibleMediaTypes).singleElement().hasToString(MediaType.APPLICATION_JSON_VALUE);
 	}
 
 	@Test // SPR-14988
@@ -237,7 +236,7 @@ class RequestMappingHandlerMappingTests {
 		RequestMappingInfo requestMappingInfo = assertComposedAnnotationMapping(RequestMethod.POST);
 
 		ConsumesRequestCondition condition = requestMappingInfo.getConsumesCondition();
-		assertThat(condition.getConsumableMediaTypes()).isEqualTo(Collections.singleton(MediaType.APPLICATION_XML));
+		assertThat(condition.getConsumableMediaTypes()).containsOnly(MediaType.APPLICATION_XML);
 	}
 
 	@PathPatternsParameterizedTest // gh-22010
@@ -458,10 +457,10 @@ class RequestMappingHandlerMappingTests {
 		assertThat(info).isNotNull();
 
 		Set<String> paths = info.getPatternValues();
-		assertThat(paths).containsExactly(path);
+		assertThat(paths).containsOnly(path);
 
 		Set<RequestMethod> methods = info.getMethodsCondition().getMethods();
-		assertThat(methods).containsExactly(requestMethod);
+		assertThat(methods).containsOnly(requestMethod);
 
 		return info;
 	}