Cover invalid selector with some tests

DEVSIX-6158

Autoported commit.
Original commit hash: [ef778b41e]

Author: ars18wrw

itext.tests/itext.styledxmlparser.tests/itext/styledxmlparser/css/parse/CssSelectorParserTest.cs

@@ -0,0 +1,40 @@
+/*
+This file is part of the iText (R) project.
+Copyright (c) 1998-2021 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/>.
+*/
+using System;
+using iText.Commons.Utils;
+using iText.StyledXmlParser.Exceptions;
+using iText.Test;
+
+namespace iText.StyledXmlParser.Css.Parse {
+    public class CssSelectorParserTest : ExtendedITextTest {
+        [NUnit.Framework.Test]
+        public virtual void SelectorBeginsWithSpaceTest() {
+            String space = " ";
+            String selectorWithSpaceAtTheBeginning = space + ".spaceBefore";
+            Exception expectedException = NUnit.Framework.Assert.Catch(typeof(ArgumentException), () => CssSelectorParser
+                .ParseSelectorItems(selectorWithSpaceAtTheBeginning));
+            NUnit.Framework.Assert.AreEqual(MessageFormatUtil.Format(StyledXmlParserExceptionMessage.INVALID_TOKEN_AT_THE_BEGINNING_OF_SELECTOR
+                , space), expectedException.Message);
+        }
+    }
+}

itext/itext.styledxmlparser/itext/styledxmlparser/css/parse/CssSelectorParser.cs

@@ -46,6 +46,7 @@ source product.
 using iText.Commons.Utils;
 using iText.StyledXmlParser.Css.Selector.Item;
 using iText.StyledXmlParser.Css.Util;
+using iText.StyledXmlParser.Exceptions;
 
 namespace iText.StyledXmlParser.Css.Parse {
     /// <summary>Utilities class to parse a CSS selector.</summary>
@@ -120,7 +121,7 @@ public static IList<ICssSelectorItem> ParseSelectorItems(String selector) {
                     case '>':
                     case '~': {
                         if (selectorItems.Count == 0) {
-                            throw new ArgumentException(MessageFormatUtil.Format("Invalid token detected in the start of the selector string: {0}"
+                            throw new ArgumentException(MessageFormatUtil.Format(StyledXmlParserExceptionMessage.INVALID_TOKEN_AT_THE_BEGINNING_OF_SELECTOR
                                 , firstChar));
                         }
                         ICssSelectorItem lastItem = selectorItems[selectorItems.Count - 1];

itext/itext.styledxmlparser/itext/styledxmlparser/exceptions/StyledXmlParserExceptionMessage.cs

@@ -25,6 +25,8 @@ You should have received a copy of the GNU Affero General Public License
 namespace iText.StyledXmlParser.Exceptions {
     /// <summary>Class containing constants to be used in exceptions in the SXP module.</summary>
     public sealed class StyledXmlParserExceptionMessage {
+        public const String INVALID_TOKEN_AT_THE_BEGINNING_OF_SELECTOR = "Invalid token detected at the beginning of the selector string: \"{0}\"";
+
         public const String READING_BYTE_LIMIT_MUST_NOT_BE_LESS_ZERO = "The reading byte limit argument must not be less than zero.";
 
         private StyledXmlParserExceptionMessage() {

port-hash

@@ -1 +1 @@
-06dd11de03686fefd5ebd4d4d714550250cd3316
+ef778b41e56e96fea5aedf97a544866e7fe6cbb6