diff --git a/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/handler/RoutePredicateHandlerMappingIntegrationTests.java b/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/handler/RoutePredicateHandlerMappingIntegrationTests.java
index a5df857b40..d14adf878d 100644
--- a/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/handler/RoutePredicateHandlerMappingIntegrationTests.java
+++ b/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/handler/RoutePredicateHandlerMappingIntegrationTests.java
@@ -34,6 +34,7 @@
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.util.DefaultUriBuilderFactory;
 
 import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
 
@@ -56,8 +57,10 @@ public static void afterClass() {
 
 	@Test
 	public void requestsToManagementPortReturn404() {
+		String baseUrl = "http://localhost:" + managementPort;
 		testClient.mutate()
-			.baseUrl("http://localhost:" + managementPort)
+			.uriBuilderFactory(new DefaultUriBuilderFactory(baseUrl))
+			.baseUrl(baseUrl)
 			.build()
 			.get()
 			.uri("/get")
@@ -69,8 +72,10 @@ public void requestsToManagementPortReturn404() {
 	@Test
 	public void requestsToManagementPortAndHostHeaderReturn404() {
 		String host = "example.com:8888";
+		String baseUrl = "http://localhost:" + managementPort;
 		testClient.mutate()
-			.baseUrl("http://localhost:" + managementPort)
+			.uriBuilderFactory(new DefaultUriBuilderFactory(baseUrl))
+			.baseUrl(baseUrl)
 			.build()
 			.get()
 			.uri("/get")
diff --git a/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/test/BaseWebClientTests.java b/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/test/BaseWebClientTests.java
index e078d923c6..20f94b9a07 100644
--- a/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/test/BaseWebClientTests.java
+++ b/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/test/BaseWebClientTests.java
@@ -42,6 +42,8 @@
 import org.springframework.test.web.reactive.server.WebTestClient;
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.util.DefaultUriBuilderFactory;
+import org.springframework.web.util.UriComponentsBuilder;
 
 import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_HANDLER_MAPPER_ATTR;
 import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR;
@@ -76,7 +78,12 @@ public void setup() throws Exception {
 	protected void setup(ClientHttpConnector httpConnector, String baseUri) {
 		this.baseUri = baseUri;
 		this.webClient = WebClient.builder().clientConnector(httpConnector).baseUrl(this.baseUri).build();
-		this.testClient = WebTestClient.bindToServer(httpConnector).baseUrl(this.baseUri).build();
+		DefaultUriBuilderFactory uriBuilderFactory = new DefaultUriBuilderFactory(this.baseUri);
+		uriBuilderFactory.setParserType(UriComponentsBuilder.ParserType.WHAT_WG);
+		this.testClient = WebTestClient.bindToServer(httpConnector)
+			.uriBuilderFactory(uriBuilderFactory)
+			.baseUrl(this.baseUri)
+			.build();
 	}
 
 	@Configuration(proxyBeanMethods = false)