[dotnet] Enable ShadowRoot to use By query mechanism

Author: RenderMichael

dotnet/src/webdriver/ShadowRoot.cs

@@ -30,7 +30,7 @@ namespace OpenQA.Selenium
     /// <summary>
     /// Provides a representation of an element's shadow root.
     /// </summary>
-    public class ShadowRoot : ISearchContext, IWrapsDriver, IWebDriverObjectReference
+    public class ShadowRoot : ISearchContext, IWrapsDriver, IWebDriverObjectReference, IFindsElement
     {
         /// <summary>
         /// The property name that represents an element shadow root in the wire protocol.
@@ -93,10 +93,21 @@ public IWebElement FindElement(By by)
                 throw new ArgumentNullException(nameof(by), "by cannot be null");
             }
 
+            return by.FindElement(this);
+        }
+
+        /// <summary>
+        /// Finds a child element matching the given mechanism and value.
+        /// </summary>
+        /// <param name="mechanism">The mechanism by which to find the element.</param>
+        /// <param name="value">The value to use to search for the element.</param>
+        /// <returns>The first <see cref="IWebElement"/> matching the given criteria.</returns>
+        public virtual IWebElement FindElement(string mechanism, string value)
+        {
             Dictionary<string, object> parameters = new Dictionary<string, object>();
             parameters.Add("id", this.shadowRootId);
-            parameters.Add("using", by.Mechanism);
-            parameters.Add("value", by.Criteria);
+            parameters.Add("using", mechanism);
+            parameters.Add("value", value);
 
             Response commandResponse = this.driver.InternalExecute(DriverCommand.FindShadowChildElement, parameters);
             return this.driver.GetElementFromResponse(commandResponse);
@@ -117,10 +128,21 @@ public ReadOnlyCollection<IWebElement> FindElements(By by)
                 throw new ArgumentNullException(nameof(by), "by cannot be null");
             }
 
+            return by.FindElements(this);
+        }
+
+        /// <summary>
+        /// Finds all child elements matching the given mechanism and value.
+        /// </summary>
+        /// <param name="mechanism">The mechanism by which to find the elements.</param>
+        /// <param name="value">The value to use to search for the elements.</param>
+        /// <returns>A collection of all of the <see cref="IWebElement">IWebElements</see> matching the given criteria.</returns>
+        public virtual ReadOnlyCollection<IWebElement> FindElements(string mechanism, string value)
+        {
             Dictionary<string, object> parameters = new Dictionary<string, object>();
             parameters.Add("id", this.shadowRootId);
-            parameters.Add("using", by.Mechanism);
-            parameters.Add("value", by.Criteria);
+            parameters.Add("using", mechanism);
+            parameters.Add("value", value);
 
             Response commandResponse = this.driver.InternalExecute(DriverCommand.FindShadowChildElements, parameters);
             return this.driver.GetElementsFromResponse(commandResponse);

dotnet/test/common/ShadowRootHandlingTest.cs

@@ -18,6 +18,7 @@
 // </copyright>
 
 using NUnit.Framework;
+using System.Collections.ObjectModel;
 
 namespace OpenQA.Selenium
 {
@@ -42,8 +43,23 @@ public void ShouldFindElementUnderShadowRoot()
             driver.Url = shadowRootPage;
             IWebElement element = driver.FindElement(By.CssSelector("custom-checkbox-element"));
             ISearchContext shadowRoot = element.GetShadowRoot();
+
             IWebElement elementInShadow = shadowRoot.FindElement(By.CssSelector("input"));
             Assert.That(elementInShadow.GetAttribute("type"), Is.EqualTo("checkbox"), "Did not find element in shadow root");
+
+            ReadOnlyCollection<IWebElement> elementsInShadow = shadowRoot.FindElements(By.CssSelector("input"));
+            Assert.That(elementsInShadow, Has.One.Items, "Did not find element in shadow root");
+            Assert.That(elementsInShadow[0].GetAttribute("type"), Is.EqualTo("checkbox"), "Did not find element in shadow root");
+        }
+
+        [Test]
+        [IgnoreBrowser(Browser.Firefox, "Firefox does not support finding Shadow DOM elements")]
+        public void ShouldUseByMethodsToFindElementsUnderShadowRoot()
+        {
+            driver.Url = shadowRootPage;
+            IWebElement element = driver.FindElement(By.CssSelector("custom-checkbox-element"));
+            ISearchContext shadowRoot = element.GetShadowRoot();
+            Assert.That(shadowRoot.FindElements(By.Id("")), Is.Empty, "Searching for elements by empty ID should return empty");
         }
 
         [Test]