Refactor Test TDS Servers. Expand functional testing of connection pooling and transient failures.

build.proj

@@ -58,9 +58,14 @@
     <NetStandardDriver Include="**/netcore/ref/Microsoft.Data.SqlClient*.csproj" />
     <AKVProvider Include="**/add-ons/**/AzureKeyVaultProvider/*.csproj" />
 
+    <UnitTests Include="**/Common/Common.csproj" />
+    <UnitTests Include="**/tools/TDS/TDS/TDS.csproj" />
+    <UnitTests Include="**/tools/TDS/TDS.EndPoint/TDS.EndPoint.csproj" />
+    <UnitTests Include="**/tools/TDS/TDS.Servers/TDS.Servers.csproj" />
     <UnitTests Include="**/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj" />
     <UnitTestsProj Include="**/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj" />
-
+
+
     <FunctionalTests Include="**/Common/Common.csproj" />
     <FunctionalTests Include="**/tools/TDS/TDS/TDS.csproj" />
     <FunctionalTests Include="**/tools/TDS/TDS.EndPoint/TDS.EndPoint.csproj" />
@@ -220,6 +225,7 @@
         -p:TestTargetOS=Windows$(TargetGroup)
         --collect "Code coverage"
         --results-directory $(ResultsDirectory)
+        --filter "category!=failing%26category!=flaky"
         --logger:"trx;LogFilePrefix=Unit-Windows$(TargetGroup)-$(TestSet)"
       </TestCommand>
       <TestCommand>$(TestCommand.Replace($([System.Environment]::NewLine), " "))</TestCommand>
@@ -240,8 +246,9 @@
         -p:TestTargetOS=Unixnetcoreapp
         --collect "Code coverage"
         --results-directory $(ResultsDirectory)
+        --filter "category!=failing%26category!=flaky"
         --logger:"trx;LogFilePrefix=Unit-Unixnetcoreapp-$(TestSet)"
-      </TestCommand>
+    </TestCommand>
       <TestCommand>$(TestCommand.Replace($([System.Environment]::NewLine), " "))</TestCommand>
     </PropertyGroup>
     <Message Text=">>> Running unit tests for Unix via command: $(TestCommand)"/>
@@ -320,7 +327,7 @@
       <TestCommand>$(TestCommand.Replace($([System.Environment]::NewLine), " "))</TestCommand>
     </PropertyGroup>
     <Message Text=">>> Running Manual test for Windows via command: $(TestCommand)" />
     <Exec ConsoleToMsBuild="true" Command="$(TestCommand)" />
   </Target>
 
   <!-- Run all Manual tests applicable to Unix. -->

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/SqlInternalConnectionTds.cs

@@ -1713,8 +1713,11 @@ private void LoginNoFailover(ServerInfo serverInfo,
                     }
 
                     if (_parser == null
-                        || TdsParserState.Closed != _parser.State
                         || IsDoNotRetryConnectError(sqlex)
+                        // If state != closed, indicates that the parser encountered an error while processing the
+                        // login response (e.g. an explicit error token). Transient network errors that impact 
+                        // connectivity will result in parser state being closed.
+                        || TdsParserState.Closed != _parser.State
                         || timeout.IsExpired)
                     {
                         // no more time to try again
@@ -1993,6 +1996,9 @@ TimeoutTimer timeout
                         throw;  // Caller will call LoginFailure()
                     }
 
+                    // TODO: It doesn't make sense to connect to an azure sql server instance with a failover partner
+                    // specified. Azure SQL Server does not support failover partners. Other availability technologies
+                    // like Failover Groups should be used instead.
                     if (!ADP.IsAzureSqlServerEndpoint(connectionOptions.DataSource) && IsConnectionDoomed)
                     {
                         throw;

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/AdapterUtil.cs

@@ -24,6 +24,7 @@
 using Microsoft.Identity.Client;
 using Microsoft.SqlServer.Server;
 using System.Security.Authentication;
+using System.Collections.Generic;
 
 #if NETFRAMEWORK
 using System.Reflection;
@@ -780,7 +781,7 @@ internal static Version GetAssemblyVersion()
         /// <remarks>This array includes endpoint URLs for Azure SQL in global, Germany, US Government,
         /// China, and Fabric environments. These endpoints are used to identify and interact with Azure SQL services 
         /// in their respective regions or environments.</remarks>
-        internal static readonly string[] s_azureSqlServerEndpoints = { AZURE_SQL,
+        internal static readonly List<string> s_azureSqlServerEndpoints = new() { AZURE_SQL,
                                                                         AZURE_SQL_GERMANY,
                                                                         AZURE_SQL_USGOV,
                                                                         AZURE_SQL_CHINA,
@@ -816,11 +817,11 @@ internal static bool IsAzureSynapseOnDemandEndpoint(string dataSource)
 
         internal static bool IsAzureSqlServerEndpoint(string dataSource)
         {
-            return IsEndpoint(dataSource, s_azureSqlServerEndpoints);
+            return IsEndpoint(dataSource, s_azureSqlServerEndpoints.AsReadOnly());
         }
 
         // This method assumes dataSource parameter is in TCP connection string format.
-        private static bool IsEndpoint(string dataSource, string[] endpoints)
+        private static bool IsEndpoint(string dataSource, IReadOnlyList<string> endpoints)
         {
             int length = dataSource.Length;
             // remove server port

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/ConnectionString/DbConnectionStringDefaults.cs

@@ -57,7 +57,7 @@ internal static class DbConnectionStringDefaults
 
         #if NETFRAMEWORK
         internal const bool ConnectionReset = true;
-        internal static readonly bool TransparentNetworkIpResolution = !LocalAppContextSwitches.DisableTnirByDefault;
+        internal static bool TransparentNetworkIpResolution => !LocalAppContextSwitches.DisableTnirByDefault;
         internal const string NetworkLibrary = "";
         #endif
     }

src/Microsoft.Data.SqlClient/tests/FunctionalTests/LocalizationTest.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Threading;
+using Microsoft.SqlServer.TDS.Servers;
 using Xunit;
 
 namespace Microsoft.Data.SqlClient.Tests
@@ -55,9 +56,9 @@ private string GetLocalizedErrorMessage(string culture)
             Thread.CurrentThread.CurrentCulture = new CultureInfo(culture);
             Thread.CurrentThread.CurrentUICulture = new CultureInfo(culture);
 
-            using TestTdsServer server = TestTdsServer.StartTestServer();
-            var connStr = server.ConnectionString;
-            connStr = connStr.Replace("localhost", "dummy");
+            using TdsServer server = new TdsServer(new TdsServerArguments() { });
+            server.Start();
+            var connStr = new SqlConnectionStringBuilder() { DataSource = $"dummy,{server.EndPoint.Port}" }.ConnectionString;
             using SqlConnection connection = new SqlConnection(connStr);
 
             try

src/Microsoft.Data.SqlClient/tests/FunctionalTests/Microsoft.Data.SqlClient.FunctionalTests.csproj

@@ -36,8 +36,6 @@
     <Compile Include="SqlBulkCopyTest.cs" />
     <Compile Include="SqlClientMetaDataCollectionNamesTest.cs" />
     <Compile Include="SqlDataAdapterTest.cs" />
-    <Compile Include="SqlConnectionBasicTests.cs" />
-    <Compile Include="SqlConnectionReadOnlyRoutingTests.cs" />
     <Compile Include="SqlCommandTest.cs" />
     <Compile Include="SqlConnectionTest.cs" />
     <Compile Include="AADAuthenticationTests.cs" />
@@ -64,8 +62,6 @@
     <Compile Include="SqlConnectionStringBuilderTest.cs" />
     <Compile Include="SerializeSqlTypesTest.cs" />
     <Compile Include="TdsParserStateObject.TestHarness.cs" />
-    <Compile Include="TestTdsServer.cs" />
-    <Compile Include="TestRoutingTdsServer.cs" />
     <Compile Include="SqlHelperTest.cs" />
     <Compile Include="..\..\src\Microsoft\Data\Common\MultipartIdentifier.cs" />
     <Compile Include="..\..\src\Microsoft\Data\SqlClient\TdsParserStateObject.Multiplexer.cs" />
@@ -91,6 +87,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
     <PackageReference Include="Microsoft.SqlServer.Types" />
     <PackageReference Include="Newtonsoft.Json" />
+    <PackageReference Include="System.Configuration.ConfigurationManager" />
     <PackageReference Include="System.Security.Cryptography.Pkcs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">