When creating test projects or upgrading an application and tests to ASP.NET Core 2.1 / .NET Core 2.1, running tests fails with assembly load exceptions like
System.IO.FileNotFoundException : Could not load file or assembly 'Microsoft.AspNetCore, Version=2.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified.
When adding references to some other libraries there are also build warnings like
warning MSB3277: Found conflicts between different versions of "Microsoft.Extensions.Options" that could not be resolved.
warning MSB3277: Found conflicts between different versions of "Microsoft.Extensions.Configuration.Abstractions" that could not be resolved.
warning MSB3277: Found conflicts between different versions of "Microsoft.AspNetCore.Hosting.Abstractions" that could not be resolved.
warning MSB3277: Found conflicts between different versions of "Microsoft.Extensions.DependencyInjection.Abstractions" that could not be resolved.
warning MSB3277: Found conflicts between different versions of "Microsoft.AspNetCore.Http.Abstractions" that could not be resolved.
warning MSB3277: Found conflicts between different versions of "Microsoft.AspNetCore.Http.Features" that could not be resolved.
How can I make test projects work for testing ASP.NET Core 2.1 applications?
AspNetCore. Mvc. Testing package is used to configure the test host and test server, the TestHost and TestServer packages don't require direct package references in the test app's project file or developer configuration in the test app.
WebApplicationFactory is a class dedicated to creating an in-memory application for use in integration and end-end testing. We can create a class that inherits from WebApplicationFactory and it will handle bootstrapping TestServer and giving us back a HttpClient that can be used for making requests.
Update: This has been made easier with 2.2 Tooling. Make sure that your dotnet --version
SDK version is at least 2.2.100
, even when buidling 2.1 applications
Just add a versionless package reference to your project while keeping the Microsoft.NET.Sdk
:
<Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <TargetFramework>netcoreapp2.1</TargetFramework> </PropertyGroup> <ItemGroup> <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="2.1.1" /> <PackageReference Include="Microsoft.AspNetCore.App" /> <!-- other references to xunit, test SDK etc. --> </ItemGroup> <ItemGroup> <ProjectReference Include="..\AspNetCoreAppToTest\AspNetCoreAppToTest.csproj" /> </ItemGroup> </Project>
Original:
ASP.NET Core 2.1 uses a new "shared framework" to run ASP.NET Core applications on. Test projects need to be modified/updated to also use this shared framework using one of the following approaches:
Change the test project's <Project>
tag in the first line to use the web SDK (Microsoft.NET.Sdk.Web
instead of Microsoft.NET.Sdk
) and add a package reference to Microsoft.AspNetCore.App
(or .All
if you are using that inside the web project) without specifying a version
The project file (.csproj) of the test project should now look like this:
<Project Sdk="Microsoft.NET.Sdk.Web"> <PropertyGroup> <TargetFramework>netcoreapp2.1</TargetFramework> </PropertyGroup> <ItemGroup> <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="2.1.1" /> <PackageReference Include="Microsoft.AspNetCore.App" /> <!-- other references to xunit, test SDK etc. --> </ItemGroup> <ItemGroup> <ProjectReference Include="..\AspNetCoreAppToTest\AspNetCoreAppToTest.csproj" /> </ItemGroup> </Project>
Alternative: Leave the Sdk
as-is and add a PackageReference
to the shared framework package but specify a version.
This can be done by simply adding a NuGet reference to Microsoft.AspNetCore.App
. However, this may cause issues since the SDK may choose to update the reference when a new patch release of the ASP.NET Core is released and the tooling is updated to reflect this. You will need update the NuGet reference for every patch release.
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