集成测试ASP.NET Core MVC时的CompilationFailedException

Question

I want to integration test an ASP.NET Core MVC WebSite. I started by adding an empty MVC WebApplication project:

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.3" />
  </ItemGroup>
  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.1" />
  </ItemGroup>
</Project>

It runs and shows the ASP.NET Core MVC sample page. Then I added an XUnit-Project:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>
    <IsPackable>false</IsPackable>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="2.0.1" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />
    <PackageReference Include="xunit" Version="2.3.1" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
    <DotNetCliToolReference Include="dotnet-xunit" Version="2.3.1" />
  </ItemGroup>
  <ItemGroup>
    <ProjectReference Include="..\WebApplication1\WebApplication1.csproj" />
  </ItemGroup>
</Project>

Where I added the nuget package Microsoft.AspNetCore.TestHost.

The following test fails with a CompilationFailedException:

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.TestHost;
using WebApplication1;
using Xunit;
public class UnitTest1
{
    [Fact]
    public async void Test1()
    {
        var builder = new WebHostBuilder()
            .UseContentRoot(@"C:\path\to\WebApplication1")
            .UseStartup<Startup>();

        var server = new TestServer(builder);
        var client = server.CreateClient();

        var _ = await client.GetAsync("/");
    }
}

Exception details:

Microsoft.AspNetCore.Mvc.Razor.Compilation.CompilationFailedException : One or more compilation failures occurred:
oxhek45x.0i3(4,62): error CS0012: The type 'Attribute' is defined in an assembly that is not referenced. You must add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.
oxhek45x.0i3(4,81): error CS0518: Predefined type 'System.String' is not defined or imported
oxhek45x.0i3(4,110): error CS0518: Predefined type 'System.Type' is not defined or imported
oxhek45x.0i3(4,11): error CS0518: Predefined type 'System.Void' is not defined or imported

#542 and #2981 describe similar problems.

I tried adding this to the test project, but it didn't help:

<ItemGroup>
  <Reference Include="netstandard" />
</ItemGroup>

And I tried replacing the MetadataReferenceFeature as described in #2981 .

Answer 1

Found a "solution" that works for me:

1. Set the Content Root to the folder of the web project
2. Copy the *.deps.json file from the output folder of the web project to the output folder of the test project

This process will be made easier in ASP.NET Core 2.1 . Found the solution here . More details about the new feature in 2.1 can be found here .

This article explains how to automize step 2:

Just add this in to your test csproj-file:

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