Fix CSS selector regex

Author: sinpru

src/FlaUI.WebDriver/Controllers/FindElementsController.cs

@@ -155,34 +155,40 @@ private Session GetSession(string sessionId)
 
         private (string strategy, string value) ParseCssSelector(string cssSelector)
         {
-            if (cssSelector.StartsWith("#"))
-            {
-                return ("id", cssSelector.Substring(1));
-            }
-            if (cssSelector.StartsWith("."))
-            {
-                return ("class name", cssSelector.Substring(1));
-            }
-
-            var nameMatch = Regex.Match(cssSelector, @"\*?\[name\s*=\s*""(.+?)""\]", RegexOptions.IgnoreCase);
+            var nameMatch = Regex.Match(cssSelector, @"^\*?\[name\s*=\s*""(.+?)""\]$", RegexOptions.IgnoreCase);
             if (nameMatch.Success)
             {
                 return ("name", UnescapeCssValue(nameMatch.Groups[1].Value));
             }
-    
-            var idMatch = Regex.Match(cssSelector, @"\*?\[id\s*=\s*""(.+?)""\]", RegexOptions.IgnoreCase);
+
+            var idMatch = Regex.Match(cssSelector, @"^#((?:[\w-]|\\[0-9a-fA-F]{1,6}\s?)+)$");
             if (idMatch.Success)
             {
                 return ("id", UnescapeCssValue(idMatch.Groups[1].Value));
             }
-    
-            var classMatch = Regex.Match(cssSelector, @"\*?\[class\s*=\s*""(.+?)""\]", RegexOptions.IgnoreCase);
+
+            var classMatch = Regex.Match(cssSelector, @"^\.((?:[\w-]|\\[0-9a-fA-F]{1,6}\s?)+)$");
             if (classMatch.Success)
             {
                 return ("class name", UnescapeCssValue(classMatch.Groups[1].Value));
             }
 
-            return ("name", cssSelector);
+            var idAttrMatch = Regex.Match(cssSelector, @"^\*?\[id\s*=\s*""(.+?)""\]$", RegexOptions.IgnoreCase);
+            if (idAttrMatch.Success)
+            {
+                return ("id", UnescapeCssValue(idAttrMatch.Groups[1].Value));
+            }
+
+            var classAttrMatch = Regex.Match(cssSelector, @"^\*?\[class\s*=\s*""(.+?)""\]$", RegexOptions.IgnoreCase);
+            if (classAttrMatch.Success)
+            {
+                return ("class name", UnescapeCssValue(classAttrMatch.Groups[1].Value));
+            }
+
+            throw WebDriverResponseException.UnsupportedOperation(
+                $"CSS selector '{cssSelector}' is not supported. Only simple selectors are allowed: " +
+                "#id, .className, [name=\"value\"], [id=\"value\"], [class=\"value\"]"
+            );
         }
 
         private string UnescapeCssValue(string cssValue)