Comment on difference in matrix variable test

Based on discussion under
https://github.com/spring-projects/spring-framework/pull/1901

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

@@ -284,6 +284,10 @@ public class RequestMappingInfoHandlerMappingTests {
 		matrixVariables = getMatrixVariables(exchange, "foo");
 		uriVariables = getUriTemplateVariables(exchange);
 
+		// Unlike Spring MVC, WebFlux currently does not support APIs like
+		// "/foo/{ids}" and URL "/foo/id=1;id=2;id=3" where the whole path
+		// segment is a sequence of name-value pairs.
+
 		assertNotNull(matrixVariables);
 		assertEquals(1, matrixVariables.size());
 		assertEquals("c", matrixVariables.getFirst("b"));

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/RequestMappingInfoHandlerMappingTests.java

@@ -355,6 +355,7 @@ public class RequestMappingInfoHandlerMappingTests {
 		uriVariables = getUriTemplateVariables(request);
 
 		assertNotNull(matrixVariables);
+		assertEquals(2, matrixVariables.size());
 		assertEquals("42", matrixVariables.getFirst("a"));
 		assertEquals("c", matrixVariables.getFirst("b"));
 		assertEquals("a=42", uriVariables.get("foo"));