Add nullability annotations to module/spring-boot-restclient-test

See gh-46587

Author: mhalbritter

module/spring-boot-restclient-test/src/main/java/org/springframework/boot/restclient/test/MockServerRestClientCustomizer.java

@@ -21,6 +21,8 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Supplier;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeanUtils;
 import org.springframework.boot.restclient.RestClientCustomizer;
 import org.springframework.http.client.BufferingClientHttpRequestFactory;
@@ -133,7 +135,7 @@ public Map<RestClient.Builder, RequestExpectationManager> getExpectationManagers
 		return this.expectationManagers;
 	}
 
-	public MockRestServiceServer getServer(RestClient.Builder restClientBuilder) {
+	public @Nullable MockRestServiceServer getServer(RestClient.Builder restClientBuilder) {
 		return this.servers.get(restClientBuilder);
 	}
 

module/spring-boot-restclient-test/src/main/java/org/springframework/boot/restclient/test/MockServerRestTemplateCustomizer.java

@@ -21,6 +21,8 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Supplier;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeanUtils;
 import org.springframework.boot.restclient.RestTemplateBuilder;
 import org.springframework.boot.restclient.RestTemplateCustomizer;
@@ -147,7 +149,7 @@ public Map<RestTemplate, RequestExpectationManager> getExpectationManagers() {
 		return this.expectationManagers;
 	}
 
-	public MockRestServiceServer getServer(RestTemplate restTemplate) {
+	public @Nullable MockRestServiceServer getServer(RestTemplate restTemplate) {
 		return this.servers.get(restTemplate);
 	}
 

module/spring-boot-restclient-test/src/main/java/org/springframework/boot/restclient/test/RootUriRequestExpectationManager.java

@@ -158,7 +158,7 @@ public static RequestExpectationManager forRestTemplate(RestTemplate restTemplat
 			RequestExpectationManager expectationManager) {
 		Assert.notNull(restTemplate, "'restTemplate' must not be null");
 		UriTemplateHandler templateHandler = restTemplate.getUriTemplateHandler();
-		if (templateHandler instanceof RootUriTemplateHandler rootHandler) {
+		if (templateHandler instanceof RootUriTemplateHandler rootHandler && rootHandler.getRootUri() != null) {
 			return new RootUriRequestExpectationManager(rootHandler.getRootUri(), expectationManager);
 		}
 		return expectationManager;

module/spring-boot-restclient-test/src/main/java/org/springframework/boot/restclient/test/package-info.java

@@ -17,4 +17,7 @@
 /**
  * RestClient and RestTemplate test utilities.
  */
+@NullMarked
 package org.springframework.boot.restclient.test;
+
+import org.jspecify.annotations.NullMarked;