Feat: Add support for Android Espresso's ViewMatcher (#447)

src/Appium.Net/Appium/Android/AndroidDriver.cs

@@ -154,6 +154,16 @@ public IReadOnlyCollection<W> FindElementsByAndroidDataMatcher(string selector)
 
         #endregion IFindByAndroidDataMatcher Members
 
+        #region IFindByAndroidViewMatcher Members
+
+        public W FindElementByAndroidViewMatcher(string selector) =>
+            FindElement(MobileSelector.AndroidViewMatcher, selector);
+
+        public IReadOnlyCollection<W> FindElementsByAndroidViewMatcher(string selector) =>
+            ConvertToExtendedWebElementCollection<W>(FindElements(MobileSelector.AndroidViewMatcher, selector));
+
+        #endregion IFindByAndroidViewMatcher Members
+
         public void StartActivity(string appPackage, string appActivity, string appWaitPackage = "",
             string appWaitActivity = "", bool stopApp = true) =>
             AndroidCommandExecutionHelper.StartActivity(this, appPackage, appActivity, appWaitPackage, appWaitActivity,

src/Appium.Net/Appium/Android/AndroidElement.cs

@@ -57,6 +57,16 @@ public IReadOnlyCollection<AppiumWebElement> FindElementsByAndroidDataMatcher(st
 
         #endregion IFindByAndroidDataMatcher Members
 
+        #region IFindByAndroidViewMatcher Members
+
+        public AppiumWebElement FindElementByAndroidViewMatcher(string selector) =>
+            FindElement(MobileSelector.AndroidViewMatcher, selector);
+
+        public IReadOnlyCollection<AppiumWebElement> FindElementsByAndroidViewMatcher(string selector) =>
+            FindElements(MobileSelector.AndroidViewMatcher, selector);
+
+        #endregion IFindByAndroidViewMatcher Members
+
         public void ReplaceValue(string value) => AndroidCommandExecutionHelper.ReplaceValue(this, Id, value);
     }
 }

src/Appium.Net/Appium/Enums/MobileSelector.cs

@@ -25,6 +25,7 @@ public class MobileSelector
         public static readonly string Accessibility = "accessibility id";
         public static readonly string AndroidUIAutomator = "-android uiautomator";
         public static readonly string AndroidDataMatcher = "-android datamatcher";
+        public static readonly string AndroidViewMatcher = "-android viewmatcher";
         public static readonly string iOSAutomatoion = "-ios uiautomation";
         public static readonly string iOSPredicateString = "-ios predicate string";
         public static readonly string iOSClassChain = "-ios class chain";

src/Appium.Net/Appium/Interfaces/IFindByAndroidViewMatcher.cs

@@ -0,0 +1,47 @@
+//Licensed under the Apache License, Version 2.0 (the "License");
+//you may not use this file except in compliance with the License.
+//See the NOTICE file distributed with this work for additional
+//information regarding copyright ownership.
+//You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+//Unless required by applicable law or agreed to in writing, software
+//distributed under the License is distributed on an "AS IS" BASIS,
+//WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//See the License for the specific language governing permissions and
+//limitations under the License.
+
+using System.Collections.Generic;
+
+namespace OpenQA.Selenium.Appium.Interfaces
+{
+    public interface IFindByAndroidViewMatcher<out W> : IFindsByFluentSelector<W> where W : IWebElement
+    {
+        /// <summary>
+        /// Finds the first element in the page that matches the Android Espresso's View Matcher selector supplied
+        /// </summary>
+        /// <param name="selector">Selector for the element.</param>
+        /// <returns>IWebElement object so that you can interact that object</returns>
+        /// <example>
+        /// <code>
+        /// IWebDriver driver = new RemoteWebDriver(new DriverOptions());
+        /// IWebElement elem = driver.FindElementByAndroidViewMatcher('elements()'))
+        /// </code>
+        /// </example>
+        W FindElementByAndroidViewMatcher(string selector);
+
+        /// <summary>
+        /// Finds a list of elements that match the Android Espresso's View Matcher selector supplied
+        /// </summary>
+        /// <param name="selector">Selector for the elements.</param>
+        /// <returns>ReadOnlyCollection of IWebElement object so that you can interact with those objects</returns>
+        /// <example>
+        /// <code>
+        /// IWebDriver driver = new RemoteWebDriver(new FirefoxOptions());
+        /// ReadOnlyCollection<![CDATA[<IWebElement>]]> elem = driver.FindElementsByAndroidViewMatcher(elements())
+        /// </code>
+        /// </example>
+        IReadOnlyCollection<W> FindElementsByAndroidViewMatcher(string selector);
+    }
+}

src/Appium.Net/Appium/MobileBy.cs

@@ -104,6 +104,15 @@ public static By AndroidUIAutomator(IUiAutomatorStatementBuilder selector) =>
         /// <returns></returns>
         public static By AndroidDataMatcher(string selector) => new ByAndroidDataMatcher(selector);
 
+        /// <summary>
+        /// This method creates a <see cref="OpenQA.Selenium.By"/> strategy
+        /// that searches for elements using Espresso's View Matcher.
+        /// <see cref="https://developer.android.com/training/testing/espresso/basics#finding-view"/>
+        /// </summary>
+        /// <param name="selector">The selector to use in finding the element.</param>
+        /// <returns></returns>
+        public static By AndroidViewMatcher(string selector) => new ByAndroidViewMatcher(selector);
+
         /// <summary>
         /// This method creates a <see cref="OpenQA.Selenium.By"/> strategy 
         /// that searches for elements using iOS UI automation.
@@ -232,6 +241,38 @@ public override string ToString() =>
             $"ByAndroidDataMatcher({selector})";
     }
 
+    /// <summary>
+    /// Finds element when the Espresso's View Matcher selector has the specified value.
+    /// <see cref="https://developer.android.com/training/testing/espresso/basics#finding-view"/>
+    /// </summary>
+    public class ByAndroidViewMatcher : MobileBy
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ByAndroidViewMatcher"/> class.
+        /// </summary>
+        /// <param name="selector">The selector to use in finding the element.</param>
+        public ByAndroidViewMatcher(string selector) : base(selector, MobileSelector.AndroidViewMatcher)
+        {
+        }
+
+        public override IWebElement FindElement(ISearchContext context)
+        {
+            if (context is IFindByAndroidViewMatcher<IWebElement> finder)
+                return finder.FindElementByAndroidViewMatcher(selector);
+            return base.FindElement(context);
+        }
+
+        public override ReadOnlyCollection<IWebElement> FindElements(ISearchContext context)
+        {
+            if (context is IFindByAndroidViewMatcher<IWebElement> finder)
+                return finder.FindElementsByAndroidViewMatcher(selector).ToList().AsReadOnly();
+            return base.FindElements(context);
+        }
+
+        public override string ToString() =>
+            $"ByAndroidViewMatcher({selector})";
+    }
+
     /// <summary>
     /// Finds element when the Ios UIAutomation selector has the specified value.
     /// <see cref="https://developer.apple.com/library/tvos/documentation/DeveloperTools/Conceptual/InstrumentsUserGuide/UIAutomation.html"/>

test/integration/Android/ElementTestEspresso.cs

@@ -43,6 +43,27 @@ public void FindByAndroidDataMatcherTest()
                 1);
         }
 
+        [Test]
+        public void FindByAndroidViewMatcherTest()
+        {
+            const string selectorData = @"{
+                'name':'withText',
+                'args':[{
+                    'name':'containsString',
+                    'args':['Preference']
+                    }
+                }]";
+
+            By byAndroidViewMatcher = new ByAndroidViewMatcher(selectorData);
+
+            Assert.AreNotEqual(
+                _driver.FindElementById("android:id/list").FindElement(byAndroidViewMatcher).Text,
+                null);
+            Assert.GreaterOrEqual(
+                _driver.FindElementById("android:id/list").FindElements(byAndroidViewMatcher).Count,
+                1);
+        }
+
         [OneTimeTearDown]
         public void AfterAll()
         {