Add missing copyright headers

styled-xml-parser/src/test/java/com/itextpdf/styledxmlparser/css/CssRuleSetTest.java

@@ -1,3 +1,25 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2022 iText Group NV
+    Authors: iText Software.
+
+    This program is offered under a commercial and under the AGPL license.
+    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.
+
+    AGPL licensing:
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 package com.itextpdf.styledxmlparser.css;
 
 import com.itextpdf.styledxmlparser.css.parse.CssRuleSetParser;