ASP.NET Core 3.1 - WebApplicationFactory - What is the correct usage for WebApplicationFactoryContentRootAttribute?

[dcs3spp]

I am learning how to use the WebApplicationFactory in ASP.NET Core 3.1. In particular I am trying to figure out the correct usage of WebApplicationFactoryContentRootAttribute

I am trying to use this attribute to set the content root for a Startup bootstrap class at ../../../Src/WebApp.

When I run dotnet test for the code below it does not appear to be referencing the WebApplicationFactoryContentRootAttribute settings.

A System.IO.DirectoryNotFoundException is thrown : 'my solution base dir'/WebApp.
The path should be 'my solution base dir'/Src/WebApp.

How do I get the derived WebApplicationFactory to recognise the WebApplicationFactoryContentRootAttribute

Integration Test

using System.IO;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

using Autofac.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.AspNetCore.Mvc.Testing;
using Xunit;
using Xunit.Abstractions;

using WebApp;
using WebApp.S3.Contracts;
using WebApp.Functional.Utilities;


/// Key should match FullName of assembly containing TStartup : WebApplicationFactory<TStartup> 
/// https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.mvc.testing.webapplicationfactorycontentrootattribute?view=aspnetcore-3.0
[assembly: WebApplicationFactoryContentRoot(
    "WebApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null",
    "../../../Src/WebApp",
    "Program.cs",
    "1")]


namespace WebApp.FunctionalTests
{
    /// <summary>
    /// Eventual Goal: Tryng to create WebApplicationFactory with content root at Src/WebApp using
    /// appsettings file derived from ASPNETCORE_ENVIRONMENT variable. If
    /// the variable is unset then defaults to appsettings.Local.json. 
    /// This will also be run in a Docker container
    /// </summary>
    public class AppTestFixture : WebApplicationFactory<Startup>
    {
        //override methods here as needed for Test purpose
    }


    public class ApiIntegrationTest : IClassFixture<AppTestFixture>
    {
        private WebApplicationFactory<Startup> _factory;
        private ITestOutputHelper _output;


        /// <summary>
        /// Initialise derived WebApplicationFactory and output stream
        /// </summary>
        /// <param name="factory"><see cref="AppTestFixture"/>, dervied WebApplicationFactory</param>
        /// <param name="output">xUnit output stream</param>
        public ApiIntegrationTest(AppTestFixture factory, ITestOutputHelper output)
        {
            const string contentRoot = "Src/WebApp";

            _factory = factory;
            _output = output;

            // sanity check for FullName property of assembly containing Startup class
            string fullName = Assembly.GetAssembly(typeof(Startup)).FullName;
            _output.WriteLine($"FullName property of assembly containing 'Startup' class => {fullName}");
        }

        /// <summary>
        /// /Users/me/Development/dotnet/blazormotiondetectionlistener/WebApp/ not found
        ///
        /// Should be path /Users/me/Development/dotnet/blazormotiondetectionlistener/Src/WebApp/
        /// </summary>
        ///
        /// <remarks>
        /// How do I use WebApplicationFactoryContentRoot attribute to correctly resolve this?
        /// </remarks>
        [Fact]
        public async Task WebApp_App_ApiController_Test()
        {
            var client = _factory.CreateClient();

            await Task.CompletedTask;
        }
    }
}

Test project

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

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>

    <IsPackable>false</IsPackable>
  </PropertyGroup>

  <ItemGroup>
    <Content Update="xunit.runner.json">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Autofac" Version="6.0.0" />
    <PackageReference Include="Microsoft.AspNetCore" Version="2.2.0" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.2.0" />
    <PackageReference Include="xunit" Version="2.4.1" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
    <PackageReference Include="coverlet.collector" Version="1.0.1" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\..\..\Src\WebApp\WebApp.csproj" />
    <ProjectReference Include="..\..\Functional\Utilities\WebApp.Functional.Utilities.csproj" />
    <ProjectReference Include="..\..\..\Src\WebApp.S3.Contracts\WebApp.S3.Contracts.csproj" />
  </ItemGroup>

</Project>

Also tried adding the Assembly attribute in the test csproj file by adding this fragment:

<Target Name="AddGitMetadaAssemblyAttributes"
          BeforeTargets="CoreGenerateAssemblyInfo">
    <ItemGroup>
        <AssemblyAttribute Include="Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactoryContentRoot">
            <_Parameter1>WebApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null</_Parameter1>
            <_Parameter2>..\..\..\Src\WebApp</_Parameter2>
            <_Parameter3>Program.cs</_Parameter3>
            <_Parameter4>1</_Parameter4>
        </AssemblyAttribute>
    </ItemGroup>
  </Target>

Can see that this adds the attribute to the generated AssemblyInfo.cs in obj/Debug/netcoreapp3.1:

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

using System;
using System.Reflection;

[assembly: System.Reflection.AssemblyCompanyAttribute("WebApp.FunctionalTests")]
[assembly: System.Reflection.AssemblyConfigurationAttribute("Debug")]
[assembly: System.Reflection.AssemblyFileVersionAttribute("1.0.0.0")]
[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0")]
[assembly: System.Reflection.AssemblyProductAttribute("WebApp.FunctionalTests")]
[assembly: System.Reflection.AssemblyTitleAttribute("WebApp.FunctionalTests")]
[assembly: System.Reflection.AssemblyVersionAttribute("1.0.0.0")]
[assembly: Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactoryContentRoot("WebApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null", "../../../Src/WebApp", "Program.cs", "1")]

So, how do I get the .NET Core WebApplicationFactory to look at 'solutiondir'/Src/WebApp instead of 'solutiondir'/WebApp'? Am I using the wrong value for the attribute key property?

According to Microsoft documentation

This constructor will infer the application content root path by searching for a WebApplicationFactoryContentRootAttribute on the assembly containing the functional tests with a key equal to the TEntryPoint assembly FullName. In case an attribute with the right key can't be found, WebApplicationFactory will fall back to searching for a solution file (*.sln) and then appending TEntryPoint assembly name to the solution directory. The application root directory will be used to discover views and content files.

I am using a key value set to the FullName of the assembly containing my Startup class. Is this correct?

[crypticviper]

I stumbled upon this post while looking for answers on how to make integration tests run within a CI task in azure devops. In my case the issue was that I was executing tests with published tests (so no solution file). Ultimately I got it to work with just the csproj changes as below

<Target Name="AddIntegrationTestAttributes" BeforeTargets="CoreGenerateAssemblyInfo"> <ItemGroup> <AssemblyAttribute Include="Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactoryContentRoot"> <_Parameter1>MyWebService.AssemblyName, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null</_Parameter1> <_Parameter2>../ArtifactDirectoryName/</_Parameter2> <_Parameter3>appsettings.json</_Parameter3> <_Parameter4>1</_Parameter4> </AssemblyAttribute> </ItemGroup> </Target>

I used the appSettings.json file as tracker as mentioned in one of the other issues:

#16978

[dcs3spp]

@baligavinod Are you setting the key value for WebApplicationFactoryContentRoot to be the FullName of the assembly for TStartup, e.g. WebApplicationFactoryContentRoot? In my case my TStartup class is derived from the live Startup class for testing purposes. The live Startup class exists in a different assembly to TStartup. I think I am encountering an issue because I am using an incorrect value for the key property of the attribute and so the factory resorts to trying to find solutiondir. If I use the live Startup class it all works.

If I use UseSolutionRelativeContentRoot it works locally. However it fails in Docker container with an InvalidOperationException informing that cannot locate solution root.

[crypticviper]

key value for WebApplicationFactoryContentRoot is just assembly name in my case. Custom web application factory implementation looks like below

CustomWebApplicationFactory : WebApplicationFactory<Startup>

Startup is the startup class living in web application project. I don't have inherited startup class in my case.

[dcs3spp]

Cheers thanks for responding @baligavinod. I am resorting to trying to create a small repository to debug my code. Thanks for responding, appreciated 👍