Not able see test cases in Text Explorer for the .net core 2 based Test project - nunit

Question

I have created a test project based on .Net Core 2 and wrote some NUnit test cases. After installing necessary NuGet packages i.e. NUnit3TestAdapter, I was able to see all test cases in "Test Explorer" and able to execute those. Now, when I looked into the project directory, I found that it's creating "obj" folder and some json files in it. So I tried to change the path of "obj" folder by modifying ".csproj" file. I provided some different path in the parameter "BaseIntermediateOutputPath" and that way, I was able to get rid of "obj" folder. The reason for providing different path was, I wanted to keep json files separate from source code.
However, after modifying that I am not able to see or execute any test cases from Test Explorer.
Is this a Microsoft bug?
Is any packages having dependency on "obj" folder?
P.S.
I am using "NUnit" and "NSubstitute" packages for my test project.
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<TargetFramework>netcoreapp2.0</TargetFramework>
<OutputPath>..\..\build\$(Configuration)\UnitTests\</OutputPath>
<BaseIntermediateOutputPath>..\..\work\$(MSBuildProjectName)\</BaseIntermediateOutputPath>
</PropertyGroup>
<Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
<ItemGroup>
<PackageReference Include="Castle.Core" Version="4.1.1" />
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0" />
<PackageReference Include="NSubstitute" Version="2.0.3" />
<PackageReference Include="NUnit" Version="3.8.1" />
<PackageReference Include="NUnit3TestAdapter" Version="3.8.0" />
</ItemGroup>
<Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
<ItemGroup>
<ProjectReference Include="..\UtilityLibrary\UtilityLibrary.csproj" />
</ItemGroup>
</Project>

Answer 1

When .NET Core projects build, they do not copy all referenced files into the bin folder. When you add Microsoft.NET.Test.Sdk to your test project, one of the things it does is add an AssemblyResolve event handler which loads other dependent assemblies from a list of searchDirectories.
BaseIntermediateOutputPath not working was reported against the VSTest project and is an issue with MSBuild. The workaround is noted in the dotnet sdk repository. From that, you need to use Sdk imports in your csproj instead of the Sdk attribute on the Project element.
<Project>
<PropertyGroup>
<BaseIntermediateOutputPath>obj\XXX\</BaseIntermediateOutputPath>
</PropertyGroup>
<Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />
<!-- Body of project -->
<Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
</Project>