[Bug]: VS 2026 Test Explorer not showing results for 40 seconds. Tests finish in 7.5s.

[emragins]

Description

Hello, I just installed and migrated to tunit from xunit (v2.*). Due to the small number of tests on a relatively new project, I did the migration by hand.

I realize this may or may not be related to something TUnit can control; but maybe you have some insight. This didn't happen until I switched.

Relevant lines from the *.csproj:

  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="FluentAssertions" Version="8.9.0" />
    <PackageReference Include="Microsoft.Extensions.Diagnostics.Testing" Version="10.5.0" />
    <PackageReference Include="NSubstitute" Version="5.3.0" />
    <PackageReference Include="TestableIO.System.IO.Abstractions" Version="22.1.1" />
    <PackageReference Include="TestableIO.System.IO.Abstractions.TestingHelpers" Version="22.1.1" />
    <PackageReference Include="TUnit" Version="1.40.10" />
  </ItemGroup>

Expected Behavior

I expect to see test results show in the test explorer window as soon as they're available.

Actual Behavior

The tests kept spinning for a total of ~40 seconds even though complete.

Steps to Reproduce

I don't think this is specific to my code.

I was able to find related issues:
https://developercommunity.microsoft.com/t/Test-Explorer-in-Visual-Studio-171410/10945859
and
xunit/xunit#3342 (reply in thread)

TUnit Version

1.40.10

.NET Version

.NET 10

Operating System

Windows

IDE / Test Runner

dotnet CLI (dotnet test / dotnet run)

Error Output / Stack Trace

Additional Context

No response

IDE-Specific Issue?

• I've confirmed this issue occurs when running via dotnet test or dotnet run, not just in my IDE

[thomhurst]

Does it finish quicker with dotnet test on the cli?

[emragins]

@thomhurst In short, no. But that did give me more information to share.

---

dotnet test would not work initially.

I got this error: Testing with VSTest target is no longer supported by Microsoft.Testing.Platform on .NET 10 SDK and later. If you use dotnet test, you should opt-in to the new dotnet test experience. For more information, see https://aka.ms/dotnet-test-mtp-error
In researching it, I was unable to get dotnet test to run even with adding <OutputType>Exe</OutputType> and explicitly adding <PackageReference Include="Microsoft.Testing.Platform.MSBuild" Version="2.2.1" /> to my project file.

But adding a global.json with

{
    "test": {
        "runner": "Microsoft.Testing.Platform"
    }
}

did allow dotnet test to run.

---

I also tested with dotnet run from the project directory. The CLI was actually slower due to, presumably, the time it took to output all the exception stack traces.

I narrowed down the slowness to a behind-the-scenes retry functionality while it tries to access an inaccessible resource. Changing the code not to retry sped everything up.

---

However, that doesn't impact that core of what I'm reporting where I was unable to see any results until all results were returned...

This test will prevent ANY results from showing in the VS Test window until the 10 seconds are up.

    public class DelayTestFailed
    {
        [Test]
        public async Task Fail()
        {
            await Task.Delay(10000);
            throw new Exception("fail");
        }
    }