Fix CSS selector support for numeric IDs and escape sequences

Author: sinpru

src/FlaUI.WebDriver/Controllers/FindElementsController.cs

@@ -60,6 +60,12 @@ private async Task<ActionResult> FindElementFrom(Func<AutomationElement> startNo
             { 
                 element = await Wait.Until(() => startNode().FindFirstByXPath(findElementRequest.Value), element => element != null, session.ImplicitWaitTimeout);
             }
+            else if (findElementRequest.Using == "css selector")
+            {
+                var (strategy, value) = ParseCssSelector(findElementRequest.Value);
+                var condition = _conditionParser.ParseCondition(session.Automation.ConditionFactory, strategy, value);
+                element = await Wait.Until(() => startNode().FindFirstDescendant(condition), element => element != null, session.ImplicitWaitTimeout);
+            }
             else 
             { 
                 var condition = _conditionParser.ParseCondition(session.Automation.ConditionFactory, findElementRequest.Using, findElementRequest.Value);
@@ -71,7 +77,7 @@ private async Task<ActionResult> FindElementFrom(Func<AutomationElement> startNo
                 return NoSuchElement(findElementRequest);
             }
 
-            var knownElement = session.GetOrAddKnownElement(element);
+        var knownElement = session.GetOrAddKnownElement(element);
             return await Task.FromResult(WebDriverResult.Success(new FindElementResponse
             {
                 ElementReference = knownElement.ElementReference,
@@ -85,6 +91,12 @@ private async Task<ActionResult> FindElementsFrom(Func<AutomationElement> startN
             {
                 elements = await Wait.Until(() => startNode().FindAllByXPath(findElementRequest.Value), elements => elements.Length > 0, session.ImplicitWaitTimeout);
             }
+            else if (findElementRequest.Using == "css selector")
+            {
+                var (strategy, value) = ParseCssSelector(findElementRequest.Value);
+                var condition = _conditionParser.ParseCondition(session.Automation.ConditionFactory, strategy, value);
+                elements = await Wait.Until(() => startNode().FindAllDescendants(condition), elements => elements.Length > 0, session.ImplicitWaitTimeout);
+            }
             else
             {
                 var condition = _conditionParser.ParseCondition(session.Automation.ConditionFactory, findElementRequest.Using, findElementRequest.Value);
@@ -140,5 +152,47 @@ private Session GetSession(string sessionId)
             session.SetLastCommandTimeToNow();
             return session;
         }
+        
+        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);
+            if (nameMatch.Success)
+            {
+                return ("name", UnescapeCssValue(nameMatch.Groups[1].Value));
+            }
+    
+            var idMatch = Regex.Match(cssSelector, @"\*?\[id\s*=\s*""(.+?)""\]", RegexOptions.IgnoreCase);
+            if (idMatch.Success)
+            {
+                return ("id", UnescapeCssValue(idMatch.Groups[1].Value));
+            }
+    
+            var classMatch = Regex.Match(cssSelector, @"\*?\[class\s*=\s*""(.+?)""\]", RegexOptions.IgnoreCase);
+            if (classMatch.Success)
+            {
+                return ("class name", UnescapeCssValue(classMatch.Groups[1].Value));
+            }
+
+            return ("name", cssSelector);
+        }
+
+        private string UnescapeCssValue(string cssValue)
+        {
+            var result = Regex.Replace(cssValue, @"\\([0-9a-fA-F]{1,6})\s?", m => 
+                ((char)Convert.ToInt32(m.Groups[1].Value, 16)).ToString());
+
+            result = Regex.Replace(result, @"\\(.)", "$1");
+    
+            return result;
+        }
     }
 }

src/FlaUI.WebDriver/Services/ConditionParser.cs

@@ -44,6 +44,7 @@ public PropertyCondition ParseCondition(ConditionFactory conditionFactory, strin
         {
             switch (@using)
             {
+                case "id":
                 case "accessibility id":
                     return conditionFactory.ByAutomationId(value);
                 case "name":