Skip to content

Tests | Add Flaky test details to ConnectionFailoverTests #4341

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
cheenamalhotra wants to merge 2 commits into
base: main
Choose a base branch
from
+101 −11
Open

Tests | Add Flaky test details to ConnectionFailoverTests #4341

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
047482f
Add Flaky test details to ConnectionFailoverTests
cheenamalhotra Jun 4, 2026
8eb1089
comments
cheenamalhotra Jun 4, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
112 changes: 101 additions & 11 deletions src/Microsoft.Data.SqlClient/tests/UnitTests/SimulatedServerTests/ConnectionFailoverTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,8 @@ public class ConnectionFailoverTests
[Trait("Category", "flaky")]
[Theory]
[InlineData(40613)]
[InlineData(42108)]
[InlineData(42109)]
[InlineData(42108)] // Flaky: [errorcode: 42108] Assert.Equal() Failure: Strings differ | Assert.Equal() Failure: Values differ
[InlineData(42109)] // Flaky: [errorcode: 42109] Assert.Equal() Failure: Strings differ
public void TransientFault_NoFailover_DoesNotClearPool(uint errorCode)
{
// When connecting to a server with a configured failover partner,
Expand Down Expand Up @@ -67,16 +67,29 @@ public void TransientFault_NoFailover_DoesNotClearPool(uint errorCode)
// Assert
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal(ConnectionState.Open, secondConnection.State);

/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Strings differ
↓ (pos 14)
Expected: "localhost,51966"
Actual: "localhost,51965"
↑ (pos 14)
*/
Assert.Equal($"localhost,{initialServer.EndPoint.Port}", connection.DataSource);
Assert.Equal($"localhost,{initialServer.EndPoint.Port}", secondConnection.DataSource);

// 1 for the initial connection, 2 for the second connection
/* TODO: Fix flaky test failure for errorcode 42108:
Assert.Equal() Failure: Values differ
Expected: 3
Actual: 4
*/
Assert.Equal(3, initialServer.PreLoginCount - initialServer.AbandonedPreLoginCount);
// A failover should not be triggered, so prelogin count to the failover server should be 0
Assert.Equal(0, failoverServer.PreLoginCount);
}

[Trait("Category", "flaky")]
[Trait("Category", "flaky")] // Assert.Equal() Failure: Values differ | System.ComponentModel.Win32Exception : The wait operation timed out.
[Fact]
public void NetworkError_TriggersFailover_ClearsPool()
{
Expand Down Expand Up @@ -115,6 +128,13 @@ public void NetworkError_TriggersFailover_ClearsPool()
// Open the initial connection to warm up the pool and populate failover partner information
// for the pool group.
using SqlConnection connection = new(builder.ConnectionString);

/* TODO: Fix flaky test failure:
Microsoft.Data.SqlClient.SqlException : A network-related or instance-specific error occurred while establishing a connection to SQL Server.
The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured
to allow remote connections. (provider: TCP Provider, error: 0 - The wait operation timed out.)
---- System.ComponentModel.Win32Exception : The wait operation timed out.
*/
connection.Open();
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal($"localhost,{initialServer.EndPoint.Port}", connection.DataSource);
Expand All @@ -131,8 +151,13 @@ public void NetworkError_TriggersFailover_ClearsPool()
Assert.Equal(ConnectionState.Open, secondConnection.State);
Assert.Equal($"localhost,{failoverServer.EndPoint.Port}", secondConnection.DataSource);
Assert.Equal(1, initialServer.PreLoginCount);
Assert.Equal(1, failoverServer.PreLoginCount);

/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Values differ
Expected: 1
Actual: 2
*/
Assert.Equal(1, failoverServer.PreLoginCount);

// Act
// Request a new connection, should initiate a fresh connection attempt if the pool was cleared.
Expand Down Expand Up @@ -242,7 +267,7 @@ public void NetworkDelay_ShouldConnectToPrimary()
}

[Fact]
[Trait("Category", "flaky")]
[Trait("Category", "flaky")] // Assert.Equal() Failure: Values differ | System.ComponentModel.Win32Exception : The wait operation timed out
public void NetworkError_WithUserProvidedPartner_RetryDisabled_ShouldConnectToFailoverPartner()
{
using TdsServer failoverServer = new(
Expand Down Expand Up @@ -277,6 +302,15 @@ public void NetworkError_WithUserProvidedPartner_RetryDisabled_ShouldConnectToFa
using SqlConnection connection = new(builder.ConnectionString);

// Act
/* TODO: Fix flaky test failure:
Microsoft.Data.SqlClient.SqlException : Connection Timeout Expired. The timeout period elapsed during the post-login phase.
The connection could have timed out while waiting for server to complete the login process and respond;
Or it could have timed out while attempting to create multiple active connections.
This failure occurred while attempting to connect to the Principle server.
The duration spent while attempting to connect to this server was - [Pre-Login] initialization=6; handshake=80;
[Login] initialization=0; authentication=0; [Post-Login] complete=5443;
---- System.ComponentModel.Win32Exception : The wait operation timed out
*/
connection.Open();


Expand All @@ -285,12 +319,18 @@ 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);

/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Values differ
Expected: 1
Actual: 2
*/
Assert.Equal(1, failoverServer.PreLoginCount);
Assert.Equal(1, server.PreLoginCount);
}

[Fact]
[Trait("Category", "flaky")]
[Trait("Category", "flaky")] // Assert.Equal() Failure: Values differ | System.ComponentModel.Win32Exception : The wait operation timed out
public void NetworkError_WithUserProvidedPartner_RetryEnabled_ShouldConnectToFailoverPartner()
{
using TdsServer failoverServer = new(
Expand Down Expand Up @@ -325,13 +365,36 @@ public void NetworkError_WithUserProvidedPartner_RetryEnabled_ShouldConnectToFai
};
using SqlConnection connection = new(builder.ConnectionString);
// Act
/* TODO: Fix flaky test failure:
Microsoft.Data.SqlClient.SqlException : Connection Timeout Expired.
The timeout period elapsed during the post-login phase.
The connection could have timed out while waiting for server to complete the login process and respond;
Or it could have timed out while attempting to create multiple active connections.
This failure occurred while attempting to connect to the Principle server.
The duration spent while attempting to connect to this server was - [Pre-Login] initialization=4; handshake=68;
[Login] initialization=0; authentication=0; [Post-Login] complete=5443;
---- System.ComponentModel.Win32Exception : The wait operation timed out
*/
/* TODO: Fix flaky test failure:
Microsoft.Data.SqlClient.SqlException : Connection Timeout Expired.
The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement.
This could be because the pre-login handshake failed or the server was unable to respond back in time.
This failure occurred while attempting to connect to the Principle server.
The duration spent while attempting to connect to this server was - [Pre-Login] initialization=0; handshake=5285;
---- System.ComponentModel.Win32Exception : The wait operation timed out.
*/
connection.Open();

// Assert
// On the first connection attempt, failover partner information is available in the connection string,
// so the connection will retry on the failover server.
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal($"localhost,{failoverServer.EndPoint.Port}", connection.DataSource);
/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Values differ
Expected: 1
Actual: 2
*/
Assert.Equal(1, server.PreLoginCount);
Assert.Equal(0, server.Login7Count);
Assert.Equal(1, failoverServer.PreLoginCount - failoverServer.AbandonedPreLoginCount);
Expand Down Expand Up @@ -448,7 +511,7 @@ public void TransientFault_RetryDisabled_ShouldFail(uint errorCode)
[InlineData(40613)]
[InlineData(42108)]
[InlineData(42109)]
[Trait("Category", "flaky")]
[Trait("Category", "flaky")] // [errorcode: 40613] Assert.Equal() Failure: Values differ
public void TransientFault_WithUserProvidedPartner_ShouldConnectToPrimary(uint errorCode)
{
// Arrange
Expand Down Expand Up @@ -490,17 +553,21 @@ public void TransientFault_WithUserProvidedPartner_ShouldConnectToPrimary(uint e
Assert.Equal($"localhost,{server.EndPoint.Port}", connection.DataSource);

// Failures should prompt the client to return to the original server, resulting in a login count of 2
/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Values differ
Expected: 2
Actual: 3
*/
Assert.Equal(2, server.PreLoginCount - server.AbandonedPreLoginCount);
// Login-phase errors must NOT trigger failover alternation
Assert.Equal(0, failoverServer.PreLoginCount);
}

[Trait("Category", "flaky")]
[Trait("Category", "flaky")] // [errorcode: 42109] Assert.Fail() Failure
[Theory]
[InlineData(40613)]
[InlineData(42108)]
[InlineData(42109)]
[Trait("Category", "flaky")]
public void TransientFault_WithUserProvidedPartner_RetryDisabled_ShouldFail(uint errorCode)
{
// Arrange
Expand Down Expand Up @@ -542,12 +609,13 @@ public void TransientFault_WithUserProvidedPartner_RetryDisabled_ShouldFail(uint
Assert.Equal((int)errorCode, e.Number);
return;
}

// TODO: Fix flaky Assert.Fail() in this test method;
// [errorcode: 42109] Assert.Fail() Failure
Assert.Fail();
}

[Fact]
[Trait("Category", "flaky")]
[Trait("Category", "flaky")] // Assert.Equal() Failure: Values differ | System.ComponentModel.Win32Exception : The wait operation timed out
public void TransientFault_IgnoreServerProvidedFailoverPartner_ShouldConnectToUserProvidedPartner()
{
// Arrange
Expand Down Expand Up @@ -585,6 +653,12 @@ public void TransientFault_IgnoreServerProvidedFailoverPartner_ShouldConnectToUs
SqlConnection connection = new(builder.ConnectionString);

// Connect once to the primary to trigger it to send the failover partner
/* TODO: Fix flaky test failure:
Microsoft.Data.SqlClient.SqlException : A network-related or instance-specific error occurred while establishing a connection to SQL Server.
The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections.
(provider: TCP Provider, error: 0 - The wait operation timed out.)
---- System.ComponentModel.Win32Exception : The wait operation timed out.
*/
connection.Open();
Assert.Equal("invalidhost", (connection.InnerConnection as SqlConnectionInternal)!.ServerProvidedFailoverPartner);

Expand All @@ -606,8 +680,21 @@ public void TransientFault_IgnoreServerProvidedFailoverPartner_ShouldConnectToUs

// Assert
Assert.Equal(ConnectionState.Open, failoverConnection.State);

/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Strings differ
↓ (pos 13)
Expected: "localhost,51479"
Actual: "localhost,51480"
↑ (pos 13)
*/
Assert.Equal($"localhost,{failoverServer.EndPoint.Port}", failoverConnection.DataSource);
// 1 for the initial connection
/* TODO: Fix flaky Assert.Equal() in this test method;
Assert.Equal() Failure: Values differ
Expected: 1
Actual: 2
*/
Assert.Equal(1, server.PreLoginCount - server.AbandonedPreLoginCount);
// 1 for the failover connection
Assert.Equal(1, failoverServer.PreLoginCount - failoverServer.AbandonedPreLoginCount);
Expand Down Expand Up @@ -789,6 +876,7 @@ public void TransientFault_WithUserProvidedPartner_Pooling_ShouldNotClearPool_No
/// and never attempts failover alternation.
/// </summary>
[Theory]
[Trait("Category", "flaky")] // Assert.Throws() Failure: No exception was thrown
Copy link
Copy Markdown
Member Author

@cheenamalhotra cheenamalhotra Jun 4, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

New flaky test also found failing in pipelines

[InlineData(40613)]
[InlineData(42108)]
[InlineData(42109)]
Expand Down Expand Up @@ -827,6 +915,8 @@ public void TransientFault_RetryDisabled_WithUserProvidedPartner_ShouldFail_NotF
using SqlConnection connection = new(builder.ConnectionString);

// No outer connect retry is allowed, so the first transient error should surface.
// TODO: Fix flakiness of Assert.Throws() in this test method; currently, if the exception is not thrown as expected,
// Assert.Throws will fail the test with an assertion failure ("No exception was thrown").
SqlException ex = Assert.Throws<SqlException>(() => connection.Open());

Assert.Equal((int)errorCode, ex.Number);
Expand Down
Loading