Allow UriTemplate to be built with an empty template

Closes gh-32437

Author: bsgrd

spring-web/src/main/java/org/springframework/web/util/UriTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -66,7 +66,7 @@ public class UriTemplate implements Serializable {
 	 * @param uriTemplate the URI template string
 	 */
 	public UriTemplate(String uriTemplate) {
-		Assert.hasText(uriTemplate, "'uriTemplate' must not be null");
+		Assert.notNull(uriTemplate, "'uriTemplate' must not be null");
 		this.uriTemplate = uriTemplate;
 		this.uriComponents = UriComponentsBuilder.fromUriString(uriTemplate).build();
 

spring-web/src/test/java/org/springframework/web/util/UriTemplateTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatNoException;
 
 /**
  * @author Arjen Poutsma
@@ -35,6 +36,16 @@
  */
 class UriTemplateTests {
 
+	@Test
+	void emptyPathDoesNotThrowException() {
+		assertThatNoException().isThrownBy(() -> new UriTemplate(""));
+	}
+
+	@Test
+	void nullPathThrowsException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new UriTemplate(null));
+	}
+
 	@Test
 	void getVariableNames() {
 		UriTemplate template = new UriTemplate("/hotels/{hotel}/bookings/{booking}");