Test discovery aborted when test project targets framework not installed on the machine

Describe the Issue

I get errors like this all the time when I open Aspire repository:

2026-05-21 08:50:10.653 [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)
2026-05-21 08:50:10.656 [error] [Aspire.Microsoft.Azure.StackExchangeRedis.Tests.dll] You must install or update .NET to run this application.

App: C:\Users\karolz\code\aspire\aspire\artifacts\bin\Aspire.Microsoft.Azure.StackExchangeRedis.Tests\Debug\net9.0\Aspire.Microsoft.Azure.StackExchangeRedis.Tests.exe
Architecture: x64
Framework: 'Microsoft.NETCore.App', version '9.0.0' (x64)
.NET location: C:\Program Files\dotnet\

The following frameworks were found:
  8.0.27 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  10.0.5 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  10.0.8 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

Learn more:
https://aka.ms/dotnet/app-launch-failed

To install missing framework, download:
https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=9.0.0&arch=x64&rid=win-x64&os=win10

2026-05-21 08:50:10.659 [error] Connection to test host 'C:\Users\karolz\code\aspire\aspire\artifacts\bin\Aspire.Microsoft.Azure.StackExchangeRedis.Tests\Debug\net9.0\Aspire.Microsoft.Azure.StackExchangeRedis.Tests.dll' was cancelled before it could be established. The test runner process did not connect within the allowed time.

Steps To Reproduce

1. Make sure you DON'T have .NET Framework 9.0
2. Clone Aspire repository https://github.com/microsoft/Aspire
3. Open repository in VS Code

Expected Behavior

It is true that I do not have the framework mentioned in the error message, but I DO have OTHER frameworks installed and I would like to be able to run tests targeting these frameworks. In vast majority of cases my tests are not framework-specific and having them pass/fail with any framework is very indicative of the correctness of the change I am working on.

Environment Information

OS: Windows, latest version
VS Code insiders, latest version
C# Dev Kit 3.20.197