DefaultServerRequest parses the path if necessary

Closes gh-25353

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultServerRequest.java

@@ -101,7 +101,11 @@ class DefaultServerRequest implements ServerRequest {
 		this.params = CollectionUtils.toMultiValueMap(new ServletParametersMap(servletRequest));
 		this.attributes = new ServletAttributesMap(servletRequest);
 
-		this.requestPath = ServletRequestPathUtils.getParsedRequestPath(servletRequest);
+		// DispatcherServlet parses the path but for other scenarios (e.g. tests) we might need to
+
+		this.requestPath = (ServletRequestPathUtils.hasParsedRequestPath(servletRequest) ?
+				ServletRequestPathUtils.getParsedRequestPath(servletRequest) :
+				ServletRequestPathUtils.parseAndCache(servletRequest));
 	}
 
 	private static List<MediaType> allSupportedMediaTypes(List<HttpMessageConverter<?>> messageConverters) {