Use assertThat from Hamcrest instead of JUnit 4

org.junit.Assert.assertThat() is deprecated as of JUnit 4.13.

See gh-22894

spring-webflux/src/test/java/org/springframework/web/reactive/DispatcherHandlerErrorTests.java

@@ -52,6 +52,7 @@ import org.springframework.web.server.handler.ExceptionHandlingWebHandler;
 
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.startsWith;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.*;
 import static org.springframework.http.MediaType.*;

spring-webflux/src/test/java/org/springframework/web/reactive/config/ResourceHandlerRegistryTests.java

@@ -49,10 +49,10 @@ import org.springframework.web.reactive.resource.ResourceWebHandler;
 import org.springframework.web.reactive.resource.VersionResourceResolver;
 import org.springframework.web.reactive.resource.WebJarsResourceResolver;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
 /**

spring-webflux/src/test/java/org/springframework/web/reactive/function/BodyInsertersTests.java

@@ -68,6 +68,7 @@ import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 
 import static java.nio.charset.StandardCharsets.*;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.springframework.http.codec.json.Jackson2CodecSupport.*;

spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java

@@ -56,6 +56,7 @@ import org.springframework.http.client.reactive.JettyClientHttpConnector;
 import org.springframework.http.client.reactive.ReactorClientHttpConnector;
 import org.springframework.http.codec.Pojo;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 
 /**

spring-webflux/src/test/java/org/springframework/web/reactive/resource/AppCacheManifestTransformerTests.java

@@ -29,6 +29,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.mock.web.test.server.MockServerWebExchange;
 import org.springframework.util.FileCopyUtils;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.springframework.mock.http.server.reactive.test.MockServerHttpRequest.*;

spring-webflux/src/test/java/org/springframework/web/reactive/resource/ResourceUrlProviderTests.java

@@ -39,6 +39,7 @@ import org.springframework.web.context.support.AnnotationConfigWebApplicationCon
 import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
 import org.springframework.web.util.pattern.PathPattern;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 import static org.springframework.mock.http.server.reactive.test.MockServerHttpRequest.*;
 

spring-webflux/src/test/java/org/springframework/web/reactive/resource/ResourceWebHandlerTests.java

@@ -55,6 +55,7 @@ import org.springframework.web.server.MethodNotAllowedException;
 import org.springframework.web.server.ResponseStatusException;
 import org.springframework.web.server.ServerWebExchange;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.ArgumentMatchers.any;

spring-webflux/src/test/java/org/springframework/web/reactive/resource/VersionResourceResolverTests.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.web.reactive.resource;
 
 import java.time.Duration;
@@ -33,6 +34,7 @@ import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.mock.web.test.server.MockServerWebExchange;
 import org.springframework.web.server.ServerWebExchange;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.BDDMockito.*;

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/HandlerMethodMappingTests.java

@@ -35,6 +35,7 @@ import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.util.pattern.PathPattern;
 import org.springframework.web.util.pattern.PathPatternParser;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 
 /**

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/InvocableHandlerMethodTests.java

@@ -42,6 +42,7 @@ import org.springframework.web.reactive.HandlerResult;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.UnsupportedMediaTypeStatusException;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.any;

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/RequestMappingInfoHandlerMappingTests.java

@@ -59,6 +59,7 @@ import org.springframework.web.server.UnsupportedMediaTypeStatusException;
 import org.springframework.web.util.pattern.PathPattern;
 
 import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 import static org.springframework.mock.http.server.reactive.test.MockServerHttpRequest.*;
 import static org.springframework.web.bind.annotation.RequestMethod.*;

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/GlobalCorsConfigIntegrationTests.java

@@ -36,6 +36,7 @@ import org.springframework.web.client.RestTemplate;
 import org.springframework.web.reactive.config.CorsRegistry;
 import org.springframework.web.reactive.config.WebFluxConfigurationSupport;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 

spring-webflux/src/test/java/org/springframework/web/reactive/socket/WebSocketIntegrationTests.java

@@ -38,6 +38,7 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 
 /**

spring-webflux/src/test/java/org/springframework/web/reactive/socket/server/support/HandshakeWebSocketServiceTests.java

@@ -33,6 +33,7 @@ import org.springframework.web.reactive.socket.WebSocketHandler;
 import org.springframework.web.reactive.socket.server.RequestUpgradeStrategy;
 import org.springframework.web.server.ServerWebExchange;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;