The test runner process did not connect within the allowed time

[glen-84]

Describe the Issue

I get this every time that I open the GraphQL Platform All.slnx solution.

2026-05-31 10:55:43.373 [info] Starting discovery for 22 sources.
2026-05-31 10:55:43.491 [error] Connection to test host '/home/glen/Programming/Projects/ChilliCream/graphql-platform/graphql-platform-3/src/Nitro/CommandLine/test/CommandLine.Tests/bin/Debug/net10.0/ChilliCream.Nitro.CommandLine.Tests.dll' was cancelled before it could be established. The test runner process did not connect within the allowed time.
2026-05-31 10:55:43.498 [error] Connection to test host '/home/glen/Programming/Projects/ChilliCream/graphql-platform/graphql-platform-3/src/HotChocolate/Json/test/Json.Tests/bin/Debug/net9.0/HotChocolate.Text.Json.Tests.dll' was cancelled before it could be established. The test runner process did not connect within the allowed time.
2026-05-31 10:55:43.504 [error] System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at Microsoft.VisualStudio.Threading.ThreadingTools.WithCancellationSlow[T](Task`1 task, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.TestWindow.Internal.RemoteAgent.TestingPlatform.Clients.TestingPlatformClientConnectionManager.LaunchTestRunnerAndWaitForMainNodeConnectionAsync(TestingPlatformLaunchConfig config, InitializeRequestArgs initializeRequest, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.TestWindow.Internal.RemoteAgent.TestingPlatform.Clients.TestingPlatformClientConnectionManager.LaunchTestRunnerAndWaitForMainNodeConnectionAsync(TestingPlatformLaunchConfig config, InitializeRequestArgs initializeRequest, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.TestWindow.Internal.RemoteAgent.TestingPlatform.Clients.TestingPlatformClient.CreateTestingPlatformClient(TestingPlatformLaunchConfig config, IProcessFactory processFactory, ITestRunDataSink dataSink, TestingPlatformCallbackHandler callback, IInternalLogger logger, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.TestWindow.Internal.RemoteAgent.TestingPlatform.Providers.DefaultProfile.CreateTestingPlatformClient(TestingPlatformLaunchConfig config, ITestRunDataSink dataSink, TestingPlatformCallbackHandler callback, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.TestWindow.Internal.RemoteAgent.TestingPlatform.Providers.ClientServerProvider.CreateTestingPlatformClient(TestingPlatformLaunchConfig config, ITestRunDataSink dataSink, TestingPlatformCallbackHandler callback, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.TestWindow.Internal.RemoteAgent.TestingPlatform.Providers.TestingPlatformClientProvider.GetOrLaunchClientAsync(String source, String launcherType, String launcherConfiguration, RunSettingsInfo runSettingsInfo, Boolean singleUse, Boolean launchDebugger, IDictionary`2 environmentVariables, CancellationToken cancellationToken)

Steps To Reproduce

1. Clone the GraphQL Platform repository.
2. Open the All.slnx solution.

Expected Behavior

No errors.

Environment Information

OS: Linux (but I believe this occurs on Windows and macOS as well)
VS Code: 1.122.1
Extension: 3.20.199

[claudiaregio]

@peterwald Could you take a look for RCA?