Resolved conflicts.

scripts/build.ps1

@@ -260,7 +260,7 @@ function Publish-Package
         Move-Item $coreCLR20PackageDir\$file $coreCLRExtensionsDir -Force
     }
 
-	# Note Note: If there are some dependencies for the TestHostRuntimeProvider assemblies, those need to be moved too. 
+	# Note Note: If there are some dependencies for the TestHostRuntimeProvider assemblies, those need to be moved too.
     $runtimeproviders = @("Microsoft.TestPlatform.TestHostRuntimeProvider.dll", "Microsoft.TestPlatform.TestHostRuntimeProvider.pdb")
     foreach($file in $runtimeproviders) {
         Write-Verbose "Move-Item $fullCLRPackageDir\$file $fullCLRExtensionsDir -Force"

src/Microsoft.TestPlatform.Client/TestPlatform.cs

@@ -86,11 +86,11 @@ public IDiscoveryRequest CreateDiscoveryRequest(DiscoveryCriteria discoveryCrite
                 throw new ArgumentNullException(nameof(discoveryCriteria));
             }
 
-            // Update cache with Extension Folder's files
             this.AddExtensionAssemblies(discoveryCriteria.RunSettings);
 
             var testHostManager = this.testHostProviderManager.GetTestHostManagerByRunConfiguration(discoveryCriteria.RunSettings);
-
+            testHostManager.Initialize(TestSessionMessageLogger.Instance, discoveryCriteria.RunSettings);
+
             var discoveryManager = this.TestEngine.GetDiscoveryManager(testHostManager, discoveryCriteria, protocolConfig);
             discoveryManager.Initialize();
 
@@ -111,7 +111,6 @@ public ITestRunRequest CreateTestRunRequest(TestRunCriteria testRunCriteria, Pro
                 throw new ArgumentNullException(nameof(testRunCriteria));
             }
 
-            // Update cache with Extension Folder's files
             this.AddExtensionAssemblies(testRunCriteria.TestRunSettings);
 
             var runConfiguration = XmlRunSettingsUtilities.GetRunConfigurationNode(testRunCriteria.TestRunSettings);
@@ -147,6 +146,19 @@ public void Dispose()
             throw new NotImplementedException();
         }
 
+        /// <summary>
+        /// The initialize.
+        /// </summary>
+        /// <param name="pathToAdditionalExtensions"> The path to additional extensions. </param>
+        /// <param name="loadOnlyWellKnownExtensions"> The load only well known extensions. </param>
+        /// <param name="forceX86Discoverer"> The force x86 discoverer. </param>
+        public void Initialize(IEnumerable<string> pathToAdditionalExtensions, bool loadOnlyWellKnownExtensions, bool forceX86Discoverer)
+        {
+            // TODO: ForceX86Discoverer options
+            this.TestEngine.GetExtensionManager()
+                 .UseAdditionalExtensions(pathToAdditionalExtensions, loadOnlyWellKnownExtensions);
+        }
+
         /// <summary>
         /// The update extensions.
         /// </summary>
@@ -186,7 +198,7 @@ private void AddExtensionAssemblies(string runSettings)
 
                     if (adapterFiles.Count > 0)
                     {
-                        this.UpdateExtensions(extensionAssemblies, true);
+                        this.UpdateExtensions(adapterFiles, true);
                     }
                 }
             }
@@ -200,16 +212,15 @@ private void AddExtensionAssemblies(string runSettings)
         /// </param>
         private void AddExtensionAssembliesFromSource(TestRunCriteria testRunCriteria)
         {
-            // Find source directories
-            var sources = testRunCriteria.Sources;
+            IEnumerable<string> sources = testRunCriteria.Sources;
             if (testRunCriteria.HasSpecificTests)
             {
                 // If the test execution is with a test filter, group them by sources
                 sources = testRunCriteria.Tests.Select(tc => tc.Source).Distinct();
             }
 
-            // Currently we support discovering loggers only from Source directory
-            var loggersToUpdate = new List<string>();
+            List<string> loggersToUpdate = new List<string>();
+
             foreach (var source in sources)
             {
                 var sourceDirectory = Path.GetDirectoryName(source);

src/Microsoft.TestPlatform.Common/ExtensionFramework/TestPluginCache.cs

@@ -54,6 +54,8 @@ public class TestPluginCache
 
         private static TestPluginCache instance;
 
+        private List<string> defaultExtensionPaths = new List<string>();
+
         #endregion
 
         #region Constructor
@@ -308,6 +310,21 @@ public void UpdateExtensions(IEnumerable<string> additionalExtensionsPath, bool
 
         #region Utility methods
 
+        internal IEnumerable<string> DefaultExtensionPaths
+        {
+            get
+            {
+                return this.defaultExtensionPaths;
+            }
+            set
+            {
+                if (value != null)
+                {
+                    this.defaultExtensionPaths.AddRange(value);
+                }
+            }
+        }
+
         /// <summary>
         ///  Checks if a directory exists
         /// </summary>
@@ -525,7 +542,7 @@ private Assembly CurrentDomainAssemblyResolve(AssemblyLoadContext loadContext, A
                 }
             }
         }
-
+        
         /// <summary>
         /// Log the extensions
         /// </summary>

src/Microsoft.TestPlatform.CrossPlatEngine/Client/ProxyDiscoveryManager.cs

@@ -6,7 +6,9 @@ namespace Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client
     using System;
     using System.Collections.Generic;
     using System.Linq;
+    using System.Text.RegularExpressions;
 
+    using Microsoft.VisualStudio.TestPlatform.Common;
     using Microsoft.VisualStudio.TestPlatform.Common.ExtensionFramework;
     using Microsoft.VisualStudio.TestPlatform.CommunicationUtilities;
     using Microsoft.VisualStudio.TestPlatform.CommunicationUtilities.Interfaces;
@@ -119,7 +121,12 @@ public override void Close()
         private void InitializeExtensions(IEnumerable<string> sources)
         {
             var sourceList = sources.ToList();
-            var extensions = this.testHostManager.GetTestPlatformExtensions(sourceList, TestPluginCache.Instance.PathToExtensions);
+            var extensions = this.testHostManager.GetTestPlatformExtensions(sourceList, TestPluginCache.Instance.DefaultExtensionPaths).ToList();
+            if (TestPluginCache.Instance.PathToExtensions != null)
+            {
+                var regex = new Regex(TestPlatformConstants.TestAdapterRegexPattern, RegexOptions.IgnoreCase);
+                extensions.AddRange(TestPluginCache.Instance.PathToExtensions.Where(ext => regex.IsMatch(ext)));
+            }
 
             // Only send this if needed.
             if (extensions.Count() > 0)

src/Microsoft.TestPlatform.CrossPlatEngine/Client/ProxyExecutionManager.cs

@@ -161,9 +161,12 @@ public void Abort()
         private void InitializeExtensions(IEnumerable<string> sources)
         {
             var sourceList = sources.ToList();
-            var extensions = this.testHostManager.GetTestPlatformExtensions(
-                sourceList,
-                TestPluginCache.Instance.PathToExtensions);
+            var extensions = this.testHostManager.GetTestPlatformExtensions(sourceList, TestPluginCache.Instance.DefaultExtensionPaths).ToList();
+            if (TestPluginCache.Instance.PathToExtensions != null)
+            {
+                var regex = new Regex(TestPlatformConstants.TestAdapterRegexPattern, RegexOptions.IgnoreCase);
+                extensions.AddRange(TestPluginCache.Instance.PathToExtensions.Where(ext => (regex.IsMatch(ext))));
+            }
 
             // Only send this if needed.
             if (extensions.Count() > 0)

src/Microsoft.TestPlatform.TestHostProvider/Microsoft.TestPlatform.TestHostProvider.csproj

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TestPlatformRoot Condition="$(TestPlatformRoot) == ''">..\..\</TestPlatformRoot>
   </PropertyGroup>

src/vstest.console/CommandLine/Executor.cs

@@ -27,19 +27,16 @@ namespace Microsoft.VisualStudio.TestPlatform.CommandLine
     using System.Diagnostics;
     using System.Diagnostics.Contracts;
     using System.Globalization;
-    using System.IO;
     using System.Linq;
     using System.Reflection;
 
     using Microsoft.VisualStudio.TestPlatform.CommandLine.Processors;
-    using Microsoft.VisualStudio.TestPlatform.CommandLine.Processors.Utilities;
-    using Microsoft.VisualStudio.TestPlatform.Common;
-    using Microsoft.VisualStudio.TestPlatform.Common.ExtensionFramework;
     using Microsoft.VisualStudio.TestPlatform.CoreUtilities.Tracing;
     using Microsoft.VisualStudio.TestPlatform.CoreUtilities.Tracing.Interfaces;
     using Microsoft.VisualStudio.TestPlatform.ObjectModel;
     using Microsoft.VisualStudio.TestPlatform.Utilities;
-    using Microsoft.VisualStudio.TestPlatform.Utilities.Helpers;
+    using Microsoft.VisualStudio.TestPlatform.CommandLine.Processors.Utilities;
+    using Microsoft.VisualStudio.TestPlatform.Common;
 
     using CommandLineResources = Microsoft.VisualStudio.TestPlatform.CommandLine.Resources.Resources;
     using Microsoft.VisualStudio.TestPlatform.Utilities.Helpers;
@@ -201,9 +198,6 @@ private int GetArgumentProcessors(string[] args, out List<IArgumentProcessor> pr
             // Initialize Runsettings with defaults
             RunSettingsManager.Instance.AddDefaultRunSettings();
 
-            // Default extensions path is required because RunTests argument processor has dependency on TestEngine, which further has dependency on TestRuntimeExtensionManager, which currently loads runtimeprovider from extensions folder.
-            this.UpdateDefaultExtensions();
-
             // Ensure we have an action argument.
             this.EnsureActionArgumentIsPresent(processors, processorFactory);
 
@@ -348,22 +342,6 @@ private void PrintSplashScreen()
             this.Output.WriteLine(string.Empty, OutputLevel.Information);
         }
 
-        private void UpdateDefaultExtensions()
-        {
-            var fileHelper = new FileHelper();
-            var extensionsFolder = Path.Combine(Path.GetDirectoryName(typeof(Executor).GetTypeInfo().Assembly.Location), "Extensions");
-            var defaultExtensionPaths = new List<string>();
-            if (fileHelper.DirectoryExists(extensionsFolder))
-            {
-                var dlls = fileHelper.EnumerateFiles(extensionsFolder, ".*.dll", SearchOption.TopDirectoryOnly);
-                defaultExtensionPaths.AddRange(dlls);
-                var exes = fileHelper.EnumerateFiles(extensionsFolder, ".*.exe", SearchOption.TopDirectoryOnly);
-                defaultExtensionPaths.AddRange(exes);
-
-                TestPluginCache.Instance.UpdateExtensions(defaultExtensionPaths, true);
-            }
-        }
-
         #endregion
     }
-}
+}

test/Microsoft.TestPlatform.Common.UnitTests/ExtensionFramework/TestPluginCacheTests.cs

@@ -170,23 +170,6 @@ public void GetDefaultResolutionPathsShouldReturnAdditionalExtensionPathsDirecto
             CollectionAssert.AreEqual(expectedExtensions, resolutionPaths.ToList());
         }
 
-        [TestMethod]
-        public void GetDefaultResolutionPathsShouldReturnDirectoryFromDefaultExtensionsPath()
-        {
-            // Setup the testable instance.
-            TestPluginCache.Instance = this.testablePluginCache;
-
-            var defaultExtensionsFile = typeof(TestPluginCache).GetTypeInfo().Assembly.Location;
-            this.testablePluginCache.DefaultExtensionPaths = new List<string>() { defaultExtensionsFile };
-
-            var resolutionPaths = TestPluginCache.Instance.GetDefaultResolutionPaths();
-
-            var currentDirectory = Path.GetDirectoryName(typeof(TestPluginCache).GetTypeInfo().Assembly.Location);
-
-            Assert.IsNotNull(resolutionPaths);
-            CollectionAssert.AreEqual(new List<string> { currentDirectory }, resolutionPaths.ToList());
-        }
-
         #endregion
 
         #region GetResolutionPaths tests

test/Microsoft.TestPlatform.CrossPlatEngine.UnitTests/Client/ProxyDiscoveryManagerTests.cs

@@ -67,7 +67,7 @@ public void InitializeShouldInitializeExtensionsIfPresent()
 
             try
             {
-                var extensions = new[] { "c:\\e1.TestAdapter.dll", "c:\\e2.TestAdapter.dll" };
+                var extensions = new[] { "c:\\e1.dll", "c:\\e2.dll" };
 
                 // Setup Mocks.
                 TestPluginCacheTests.SetupMockAdditionalPathExtensions(extensions);
@@ -94,13 +94,13 @@ public void InitializeShouldQueryTestHostManagerForExtensions()
             TestPluginCache.Instance = null;
             try
             {
-                TestPluginCacheTests.SetupMockAdditionalPathExtensions(new[] { "c:\\e1.TestAdapter.dll" });
+                TestPluginCacheTests.SetupMockAdditionalPathExtensions(new[] { "c:\\e1.dll" });
                 this.mockRequestSender.Setup(s => s.WaitForRequestHandlerConnection(It.IsAny<int>())).Returns(true);
                 this.mockTestHostManager.Setup(th => th.GetTestPlatformExtensions(It.IsAny<IEnumerable<string>>(), It.IsAny<IEnumerable<string>>())).Returns(new[] { "he1.dll", "c:\\e1.dll" });
 
                 this.testDiscoveryManager.Initialize();
 
-                this.mockRequestSender.Verify(s => s.InitializeDiscovery(new[] { "he1.dll", "c:\\e1.TestAdapter.dll" }, true), Times.Once);
+                this.mockRequestSender.Verify(s => s.InitializeDiscovery(new[] { "he1.dll", "c:\\e1.dll" }, true), Times.Once);
             }
             finally
             {