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

build.proj

@@ -58,6 +58,7 @@
     <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" />
@@ -230,7 +231,7 @@
       <TestCommand>$(TestCommand.Replace($([System.Environment]::NewLine), " "))</TestCommand>
     </PropertyGroup>
     <Message Text=">>> Running unit tests for Windows via command: $(TestCommand)"/>
     <Exec ConsoleToMsBuild="true" Command="$(TestCommand)"/>
   </Target>
 
   <!-- Run all unit tests applicable to Unix. -->
@@ -326,7 +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/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/UnitTests/ADPHelper.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Microsoft.Data.Common
+{
+    internal class ADPHelper : IDisposable
+    {
+        List<string> _originalAzureSqlServerEndpoints;
+
+        internal ADPHelper()
+        {
+            _originalAzureSqlServerEndpoints = [.. ADP.s_azureSqlServerEndpoints];
+        }
+
+        internal void AddAzureSqlServerEndpoint(string endpoint)
+        {
+            ADP.s_azureSqlServerEndpoints.Add(endpoint);
+        }
+
+        public void Dispose()
+        {
+            ADP.s_azureSqlServerEndpoints.Clear();
+            ADP.s_azureSqlServerEndpoints.AddRange(_originalAzureSqlServerEndpoints);
+        }
+    }
+}

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

@@ -29,6 +29,7 @@
     <ProjectReference Include="$(TestsPath)tools\TDS\TDS.Servers\TDS.Servers.csproj" />
     <ProjectReference Include="$(TestsPath)tools\TDS\TDS.EndPoint\TDS.EndPoint.csproj" />
     <ProjectReference Include="$(TestsPath)tools\TDS\TDS\TDS.csproj" />
+    <ProjectReference Include="$(TestsPath)Common\Common.csproj" />
   </ItemGroup>
   <!-- .NET Framework references -->
   <ItemGroup Condition="$(TargetGroup) == 'netfx'">

src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/SqlConnectionStringTest.cs

@@ -0,0 +1,68 @@
+using System;
+using Microsoft.Data.SqlClient.Tests.Common;
+using Xunit;
+using static Microsoft.Data.SqlClient.Tests.Common.LocalAppContextSwitchesHelper;
+
+namespace Microsoft.Data.SqlClient.UnitTests.Microsoft.Data.SqlClient
+{
+    public class SqlConnectionStringTest : IDisposable
+    {
+        private LocalAppContextSwitchesHelper _appContextSwitchHelper;
+        public SqlConnectionStringTest()
+        {
+            // Ensure that the app context switch is set to the default value
+            _appContextSwitchHelper = new LocalAppContextSwitchesHelper();
+        }
+
+#if NETFRAMEWORK
+        [Theory]
+        [InlineData("test.database.windows.net", true, Tristate.True, true)]
+        [InlineData("test.database.windows.net", false, Tristate.True, false)]
+        [InlineData("test.database.windows.net", null, Tristate.True, false)]
+        [InlineData("test.database.windows.net", true, Tristate.False, true)]
+        [InlineData("test.database.windows.net", false, Tristate.False, false)]
+        [InlineData("test.database.windows.net", null, Tristate.False, true)]
+        [InlineData("test.database.windows.net", true, Tristate.NotInitialized, true)]
+        [InlineData("test.database.windows.net", false, Tristate.NotInitialized, false)]
+        [InlineData("test.database.windows.net", null, Tristate.NotInitialized, true)]
+        [InlineData("my.test.server", true, Tristate.True, true)]
+        [InlineData("my.test.server", false, Tristate.True, false)]
+        [InlineData("my.test.server", null, Tristate.True, false)]
+        [InlineData("my.test.server", true, Tristate.False, true)]
+        [InlineData("my.test.server", false, Tristate.False, false)]
+        [InlineData("my.test.server", null, Tristate.False, true)]
+        [InlineData("my.test.server", true, Tristate.NotInitialized, true)]
+        [InlineData("my.test.server", false, Tristate.NotInitialized, false)]
+        [InlineData("my.test.server", null, Tristate.NotInitialized, true)]
+        public void TestDefaultTNIR(string dataSource, bool? tnirEnabledInConnString, Tristate tnirDisabledAppContext, bool expectedValue)
+        {
+            // Note: TNIR is only supported on .NET Framework.
+            // Note: TNIR is disabled by default for Azure SQL Database servers (i.e. *.database.windows.net)
+            // and when using federated auth unless explicitly set in the connection string.
+            // However, this evaluation only happens at login time so TNIR behavior may not match
+            // the value of TransparentNetworkIPResolution property in SqlConnectionString.
+
+            // Arrange
+            _appContextSwitchHelper.DisableTnirByDefaultField = tnirDisabledAppContext;
+
+            // Act
+            SqlConnectionStringBuilder builder = new();
+            builder.DataSource = dataSource;
+            if (tnirEnabledInConnString.HasValue)
+            {
+                builder.TransparentNetworkIPResolution = tnirEnabledInConnString.Value;
+            }
+            SqlConnectionString connectionString = new(builder.ConnectionString);
+
+            // Assert
+            Assert.Equal(expectedValue, connectionString.TransparentNetworkIPResolution);
+        }
+#endif
+
+        public void Dispose()
+        {
+            // Clean up any resources if necessary
+            _appContextSwitchHelper.Dispose();
+        }
+    }
+}

src/Microsoft.Data.SqlClient/tests/UnitTests/SimulatedServerTests/ConnectionFailoverTests.cs

@@ -9,6 +9,7 @@
 
 namespace Microsoft.Data.SqlClient.ScenarioTests
 {
+    [Collection("SimulatedServerTests")]
     public class ConnectionFailoverTests
     {
         //TODO parameterize for transient errors
@@ -31,7 +32,7 @@ public void TransientFault_NoFailover_DoesNotClearPool(uint errorCode)
             var failoverDataSource = $"localhost,{failoverServer.EndPoint.Port}";
 
             // Errors are off to start to allow the pool to warm up
-            using TransientFaultTdsServer initialServer = new TransientFaultTdsServer(new TransientFaultTdsServerArguments
+            using TransientTdsErrorTdsServer initialServer = new TransientTdsErrorTdsServer(new TransientTdsErrorTdsServerArguments
             {
                 FailoverPartner = failoverDataSource
             });
@@ -87,7 +88,7 @@ public void NetworkError_TriggersFailover_ClearsPool()
             var failoverDataSource = $"localhost,{failoverServer.EndPoint.Port}";
 
             // Errors are off to start to allow the pool to warm up
-            using TransientFaultTdsServer initialServer = new TransientFaultTdsServer(new TransientFaultTdsServerArguments
+            using TdsServer initialServer = new TdsServer(new TdsServerArguments
             {
                 FailoverPartner = failoverDataSource
             });
@@ -99,7 +100,11 @@ public void NetworkError_TriggersFailover_ClearsPool()
                 ConnectRetryInterval = 1,
                 ConnectTimeout = 30,
                 Encrypt = SqlConnectionEncryptOption.Optional,
-                InitialCatalog = "test"
+                InitialCatalog = "test",
+                MultiSubnetFailover = false,
+#if NETFRAMEWORK
+                TransparentNetworkIPResolution = false,
+#endif
             };
 
             // Open the initial connection to warm up the pool and populate failover partner information
@@ -136,9 +141,8 @@ public void NetworkError_TriggersFailover_ClearsPool()
             Assert.Equal(2, failoverServer.PreLoginCount);
         }
 
-        [ActiveIssue("https://github.com/dotnet/SqlClient/issues/3527")]
         [Fact]
-        public void NetworkError_RetryDisabled_ShouldFail()
+        public void NetworkTimeout_ShouldFail()
         {
             using TdsServer failoverServer = new TdsServer(
                 new TdsServerArguments
@@ -152,8 +156,8 @@ public void NetworkError_RetryDisabled_ShouldFail()
             using TransientDelayTdsServer server = new TransientDelayTdsServer(
                 new TransientDelayTdsServerArguments()
                 {
-                    IsEnabledTransientTimeout = true,
-                    SleepDuration = TimeSpan.FromMilliseconds(1000),
+                    IsEnabledTransientDelay = true,
+                    DelayDuration = TimeSpan.FromMilliseconds(2000),
                     FailoverPartner = $"localhost,{failoverServer.EndPoint.Port}",
                 });
             server.Start();
@@ -162,27 +166,29 @@ public void NetworkError_RetryDisabled_ShouldFail()
             {
                 DataSource = "localhost," + server.EndPoint.Port,
                 InitialCatalog = "master",// Required for failover partner to work
-                ConnectTimeout = 5,
+                ConnectTimeout = 1,
                 ConnectRetryInterval = 1,
                 ConnectRetryCount = 0, // Disable retry 
                 Encrypt = false,
+                MultiSubnetFailover = false,
+#if NETFRAMEWORK
+                TransparentNetworkIPResolution = false,
+#endif
             };
             using SqlConnection connection = new(builder.ConnectionString);
 
             // Act
-            Assert.Throws<SqlException>(() => connection.Open());
+            var e = Assert.Throws<SqlException>(() => connection.Open());
 
             // Assert
-            // On the first connection attempt, no failover partner information is available,
-            // so the connection will retry on the same server.
+            Assert.Contains("Connection Timeout Expired", e.Message);
             Assert.Equal(ConnectionState.Closed, connection.State);
             Assert.Equal(1, server.PreLoginCount);
             Assert.Equal(0, failoverServer.PreLoginCount);
         }
 
-        [ActiveIssue("https://github.com/dotnet/SqlClient/issues/3528")]
         [Fact]
-        public void NetworkError_RetryEnabled_ShouldConnectToPrimary()
+        public void NetworkDelay_ShouldConnectToPrimary()
         {
             using TdsServer failoverServer = new TdsServer(
                 new TdsServerArguments
@@ -196,8 +202,8 @@ public void NetworkError_RetryEnabled_ShouldConnectToPrimary()
             using TransientDelayTdsServer server = new TransientDelayTdsServer(
                 new TransientDelayTdsServerArguments()
                 {
-                    IsEnabledTransientTimeout = true,
-                    SleepDuration = TimeSpan.FromMilliseconds(1000),
+                    IsEnabledTransientDelay = true,
+                    DelayDuration = TimeSpan.FromMilliseconds(1000),
                     FailoverPartner = $"localhost,{failoverServer.EndPoint.Port}",
                 });
             server.Start();
@@ -207,8 +213,11 @@ public void NetworkError_RetryEnabled_ShouldConnectToPrimary()
                 DataSource = "localhost," + server.EndPoint.Port,
                 InitialCatalog = "master",// Required for failover partner to work
                 ConnectTimeout = 5,
-                ConnectRetryInterval = 1,
                 Encrypt = false,
+                MultiSubnetFailover = false,
+#if NETFRAMEWORK
+                TransparentNetworkIPResolution = false,
+#endif
             };
             using SqlConnection connection = new(builder.ConnectionString);
             try
@@ -226,7 +235,7 @@ public void NetworkError_RetryEnabled_ShouldConnectToPrimary()
             // so the connection will retry on the same server.
             Assert.Equal(ConnectionState.Open, connection.State);
             Assert.Equal($"localhost,{server.EndPoint.Port}", connection.DataSource);
-            Assert.Equal(2, server.PreLoginCount);
+            Assert.Equal(1, server.PreLoginCount);
             Assert.Equal(0, failoverServer.PreLoginCount);
         }
 
@@ -245,8 +254,8 @@ public void NetworkError_WithUserProvidedPartner_RetryDisabled_ShouldConnectToFa
             using TransientDelayTdsServer server = new TransientDelayTdsServer(
                 new TransientDelayTdsServerArguments()
                 {
-                    IsEnabledTransientTimeout = true,
-                    SleepDuration = TimeSpan.FromMilliseconds(5000),
+                    IsEnabledTransientDelay = true,
+                    DelayDuration = TimeSpan.FromMilliseconds(10000),
                     FailoverPartner = $"localhost,{failoverServer.EndPoint.Port}",
                 });
             server.Start();
@@ -277,8 +286,8 @@ public void NetworkError_WithUserProvidedPartner_RetryDisabled_ShouldConnectToFa
             // so the connection will retry on the failover server.
             Assert.Equal(ConnectionState.Open, connection.State);
             Assert.Equal($"localhost,{failoverServer.EndPoint.Port}", connection.DataSource);
-            Assert.Equal(1, server.PreLoginCount);
             Assert.Equal(1, failoverServer.PreLoginCount);
+            Assert.Equal(1, server.PreLoginCount);
         }
 
         [Fact]
@@ -296,8 +305,8 @@ public void NetworkError_WithUserProvidedPartner_RetryEnabled_ShouldConnectToFai
             using TransientDelayTdsServer server = new TransientDelayTdsServer(
                 new TransientDelayTdsServerArguments()
                 {
-                    IsEnabledTransientTimeout = true,
-                    SleepDuration = TimeSpan.FromMilliseconds(1000),
+                    IsEnabledTransientDelay = true,
+                    DelayDuration = TimeSpan.FromMilliseconds(10000),
                     FailoverPartner = $"localhost,{failoverServer.EndPoint.Port}",
                 });
             server.Start();
@@ -346,8 +355,8 @@ public void TransientFault_ShouldConnectToPrimary(uint errorCode)
                 });
             failoverServer.Start();
 
-            using TransientFaultTdsServer server = new TransientFaultTdsServer(
-                new TransientFaultTdsServerArguments()
+            using TransientTdsErrorTdsServer server = new TransientTdsErrorTdsServer(
+                new TransientTdsErrorTdsServerArguments()
                 {
                     IsEnabledTransientError = true,
                     Number = errorCode,
@@ -397,8 +406,8 @@ public void TransientFault_RetryDisabled_ShouldFail(uint errorCode)
                 });
             failoverServer.Start();
 
-            using TransientFaultTdsServer server = new TransientFaultTdsServer(
-                new TransientFaultTdsServerArguments()
+            using TransientTdsErrorTdsServer server = new TransientTdsErrorTdsServer(
+                new TransientTdsErrorTdsServerArguments()
                 {
                     IsEnabledTransientError = true,
                     Number = errorCode,
@@ -445,8 +454,8 @@ public void TransientFault_WithUserProvidedPartner_ShouldConnectToPrimary(uint e
                 });
             failoverServer.Start();
 
-            using TransientFaultTdsServer server = new TransientFaultTdsServer(
-                new TransientFaultTdsServerArguments()
+            using TransientTdsErrorTdsServer server = new TransientTdsErrorTdsServer(
+                new TransientTdsErrorTdsServerArguments()
                 {
                     IsEnabledTransientError = true,
                     Number = errorCode,
@@ -497,8 +506,8 @@ public void TransientFault_WithUserProvidedPartner_RetryDisabled_ShouldFail(uint
                 });
             failoverServer.Start();
 
-            using TransientFaultTdsServer server = new TransientFaultTdsServer(
-                new TransientFaultTdsServerArguments()
+            using TransientTdsErrorTdsServer server = new TransientTdsErrorTdsServer(
+                new TransientTdsErrorTdsServerArguments()
                 {
                     IsEnabledTransientError = true,
                     Number = errorCode,

src/Microsoft.Data.SqlClient/tests/UnitTests/SimulatedServerTests/ConnectionReadOnlyRoutingTests.cs

@@ -11,6 +11,7 @@
 
 namespace Microsoft.Data.SqlClient.ScenarioTests
 {
+    [Collection("SimulatedServerTests")]
     public class ConnectionReadOnlyRoutingTests
     {
         [Fact]