Integration tests with ASP.NET Core causes missing references from Razor files

[BrianVallelunga]

Title

Integration tests with ASP.NET Core causes missing references from Razor files

Functional impact

When attempting to run an integration test against an ASP.NET Core 1.1.1 site using the full .NET Framework, Razor views are unable to resolve references to namespaces like System

Minimal repro steps

1. Build the attached
   IntegrationTestSample.zip
   solution.
2. Run the site and confirm the home index page works
3. Use the Test Explorer to run the GetHomeReturnsOKAsync test

Expected result

The test should pass with a successful OK response from the server.

Actual result

The test fails with errors such as:

[xUnit.net 00:00:06.8955637] XUnitTestProject1.Tests.GetHomeReturnsOKAsync [FAIL]
[xUnit.net 00:00:06.8973988] Microsoft.AspNetCore.Mvc.Razor.Compilation.CompilationFailedException : One or more compilation failures occurred:
[xUnit.net 00:00:06.8978938] 0q2sc41d.qfp(10,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
[xUnit.net 00:00:06.8984156] 0q2sc41d.qfp(11,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
[xUnit.net 00:00:06.8988809] 0q2sc41d.qfp(12,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
[xUnit.net 00:00:06.8993828] 0q2sc41d.qfp(15,36): error CS0234: The type or namespace name 'ViewFeatures' does not exist in the namespace 'Microsoft.AspNetCore.Mvc' (are you missing an assembly reference?)
[xUnit.net 00:00:06.8998931] 0q2sc41d.qfp(16,11): error CS0246: The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?)
[xUnit.net 00:00:06.9003332] 0q2sc41d.qfp(18,86): error CS1980: Cannot define a class or member that utilizes 'dynamic' because the compiler required type 'System.Runtime.CompilerServices.DynamicAttribute' cannot be found. Are you missing a reference?
[xUnit.net 00:00:06.9007670] 0q2sc41d.qfp(18,86): error CS0518: Predefined type 'System.Boolean' is not defined or imported

Further technical details

This seems to be a regression of #755 and aspnet/Mvc#4686

Unlike those other issues, there is no third project involved here. Just the site and test projects.

This was not an issue until we switched to VS 2017 from VS 2015 (with project.json and xproj).

[rynowak]

/cc @pranavkm

[BrianVallelunga]

Can anyone reproduce this with the sample I uploaded?

[aruss]

Same problem here. With the previous Version it worked as I upgraded to the latest one I can not run integration tests anymore. Also tried your code and it does not work.

[hhalim]

@BrianVallelunga I can reproduce using the sample you provided. I also experienced the issue with @using in View not working with referencing dll directly. The dll was created in .net 4.6.1 and my web app is .net core 1.1.1 running in full .net framework in VS2017. I believe this is similar to issue 4686.

[BrianVallelunga]

Thanks for the confirmation. Hopefully we can get a workaround soon. This is holding up our move to VS 2017 right now.

[NTaylorMullen]

This looks like similar issues we encountered when migrating MVC. Give this a try.

[BrianVallelunga]

@NTaylorMullen I tried your suggestion and even manually copied the .deps.json file over to the test project. Unfortunately this did not fix the issue, though I agree that it seems like it could be related.

[BrianVallelunga]

Can someone from Microsoft please comment on this?

[rynowak]

@pranavkm @NTaylorMullen - any more suggestions here?

[rynowak]

@BrianVallelunga - Hi, I tried your project and was able to reproduce the failure, as well as fix it.

These are a few known issues that we've already worked around in our (MVC team) functional tests. We need to do a better job getting this information out there. I've also started a conversation internally about how we can make this much much easier to figure out for simple MVC apps.

Here's the complete project file with the fixes in place:

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

  <PropertyGroup>    
    <TargetFramework>net461</TargetFramework>
    <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
    <PreserveCompilationContext>true</PreserveCompilationContext>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="1.1.1" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
    <PackageReference Include="xunit" Version="2.2.0" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\IntegrationTestSite\IntegrationTestSite.csproj" />
  </ItemGroup>

  <ItemGroup>
    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
  </ItemGroup>
  
  <ItemGroup>
    <None Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
  </ItemGroup>

  <!--
    Work around https://github.com/NuGet/Home/issues/4412. MVC uses DependencyContext.Load() which looks next to a .dll
    for a .deps.json. Information isn't available elsewhere. Need the .deps.json file for all web site applications.
  -->
  <Target Name="CopyDepsFiles" AfterTargets="Build" Condition="'$(TargetFramework)'!=''">
    <ItemGroup>
      <DepsFilePaths Include="$([System.IO.Path]::ChangeExtension('%(_ResolvedProjectReferencePaths.FullPath)', '.deps.json'))" />
    </ItemGroup>

    <Copy SourceFiles="%(DepsFilePaths.FullPath)" DestinationFolder="$(OutputPath)" Condition="Exists('%(DepsFilePaths.FullPath)')" />
  </Target>
</Project>

You also need to create an xunit.runner.json - that is just configuration for the xunit runner. The only thing we really need is to disable shadow copy so that the tests run from the bin\Debug\net461 directory.

{
  "shadowCopy": false
}

The juicy workaround here is to get the IntegrationTestSite into the build output directory - that's needed in conjunction with disabling shadow copy.

[BrianVallelunga]

I can confirm that this fixes my issue in my main codebase. Thank you for the help and I would encourage this information to be publicized. I'm astounded more people haven't run into this.