MaxParallelThreads does not work with Conservative parallelAlgorithm

[StanislavKlo]

Describe the bug
I've created small project with Xunit.DependencyInjection v9.8.0 with 2 simple test classes (just copy paste to reproduce the issue) :

using Xunit;

[assembly: CollectionBehavior(DisableTestParallelization = false, MaxParallelThreads = 1)] 
namespace Test.Xunit.Project;

public class Class1
{
    [Fact]
    public async Task TestOne()
    {
        await Task.Delay(10000);
        Assert.True(true);
    }
} 

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <TargetFramework>net8.0</TargetFramework>
        <ImplicitUsings>enable</ImplicitUsings>
        <Nullable>enable</Nullable>
    </PropertyGroup>

    <ItemGroup>
      <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
      <PackageReference Include="xunit.assert" Version="2.9.3" />
      <PackageReference Include="Xunit.DependencyInjection" Version="9.8.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
    </ItemGroup>
    
     <PropertyGroup>
    <ParallelizationMode>Enhance</ParallelizationMode>
  </PropertyGroup>

    <ItemGroup>
      <None Update="appsettings.json">
        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
      </None>
    </ItemGroup>

</Project>

When I run both classes, I expect that they are run sequentially (because MaxParallelThreads = 1), but they run in parallel. Meanwhile, when I use the xunit package without your library, it works perfectly, running as many tests as I specify in MaxParallelThreads.

I saw a similar issue which was closed: #111 (comment), but this does not work for me.

Could you please elaborate and suggest a fix?

[StanislavKlo]

Hi @pengweiqhca, any updates on this?