Defer new pool class to next PR. Add test to boost code coverage.

Author: mdaigle

src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj

@@ -95,9 +95,6 @@
     <Compile Include="$(CommonSourceRoot)\Microsoft\Data\ProviderBase\DbConnectionFactory.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionFactory.cs</Link>
     </Compile>
-    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs">
-      <Link>Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs</Link>
-    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs">
       <Link>Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs</Link>
     </Compile>

src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj

@@ -279,9 +279,6 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionInternal.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionInternal.cs</Link>
     </Compile>
-    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs">
-      <Link>Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs</Link>
-    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs">
       <Link>Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs</Link>
     </Compile>

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPool.cs

@@ -5,6 +5,7 @@
 
 using Microsoft.Data.Common;
 using Microsoft.Data.ProviderBase;
+using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -189,8 +190,7 @@ internal IDbConnectionPool GetConnectionPool(DbConnectionFactory connectionFacto
                                 IDbConnectionPool newPool;
                                 if (LocalAppContextSwitches.UseConnectionPoolV2)
                                 {
-                                    // ChannelDbConnectionPool is the v2 pool implementation
-                                    newPool = new ChannelDbConnectionPool();
+                                    throw new NotImplementedException();
                                 }
                                 else
                                 {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/DbConnectionPoolGroup.cs

@@ -73,6 +73,31 @@ public static void BasicConnectionPoolingTest(string connectionString)
             }
         }
 
+        /// <summary>
+        /// Tests that when UseConnectionPoolV2 context switch is enabled, opening a connection throws NotImplementedException
+        /// </summary>
+        [ConditionalTheory(typeof(DataTestUtility), nameof(DataTestUtility.AreConnStringsSetup))]
+        [ClassData(typeof(ConnectionPoolConnectionStringProvider))]
+        public static void UseConnectionPoolV2ThrowsNotImplemented(string connectionString)
+        {
+            try
+            {
+                // Enable the UseConnectionPoolV2 context switch
+                AppContext.SetSwitch("Switch.Microsoft.Data.SqlClient.UseConnectionPoolV2", true);
+
+                using (SqlConnection connection = new SqlConnection(connectionString))
+                {
+                    // This should throw NotImplementedException
+                    Assert.Throws<NotImplementedException>(() => connection.Open());
+                }
+            }
+            finally
+            {
+                // Reset the context switch
+                AppContext.SetSwitch("Switch.Microsoft.Data.SqlClient.UseConnectionPoolV2", false);
+            }
+        }
+
         [ConditionalFact(typeof(DataTestUtility), nameof(DataTestUtility.IsAADPasswordConnStrSetup), nameof(DataTestUtility.IsAADAuthorityURLSetup))]
         public static void AccessTokenConnectionPoolingTest()
         {
@@ -199,6 +224,8 @@ public static void MaxPoolWaitForConnectionTest(string connectionString)
             Assert.Equal(TaskStatus.RanToCompletion, waitTask.Status);
         }
 
+        
+
         internal static InternalConnectionWrapper ReplacementConnectionUsesSemaphoreTask(string connectionString, Barrier syncBarrier)
         {
             InternalConnectionWrapper internalConnection = null;