TestFixture.cs

using System;
using System.IO;
using System.Net.Http;
using System.Reflection;
using AllReady.Models;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.ApplicationParts;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.ViewComponents;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Extensions.DependencyInjection;

namespace AllReady.IntegrationTests
{
    public class TestFixture<TStartup> : IDisposable
    {
        private readonly TestServer _server;

        public TestFixture()
        {
            var startupAssembly = typeof(TStartup).GetTypeInfo().BaseType.Assembly;
            var contentRoot = GetProjectPath(startupAssembly);

            var builder = new WebHostBuilder()
                .UseContentRoot(contentRoot)
                .ConfigureServices(InitializeServices)
                .UseEnvironment("Development")
                .UseStartup(typeof(TStartup));

            _server = new TestServer(builder);

            DbContext = _server.Host.Services.GetService(typeof(AllReadyContext)) as AllReadyContext;

            Client = _server.CreateClient();
            Client.BaseAddress = new Uri("http://localhost");
        }

        public HttpClient Client { get; }

        public AllReadyContext DbContext { get; }

        public void Dispose()
        {
            Client.Dispose();
            _server.Dispose();
        }

        protected virtual void InitializeServices(IServiceCollection services)
        {
            var startupAssembly = typeof(TStartup).GetTypeInfo().Assembly;
            var manager = new ApplicationPartManager();
            manager.ApplicationParts.Add(new AssemblyPart(startupAssembly));
            manager.FeatureProviders.Add(new ControllerFeatureProvider());
            manager.FeatureProviders.Add(new ViewComponentFeatureProvider());
            services.AddSingleton(manager);
        }

        // Get the full path to the target project for testing
        private static string GetProjectPath(Assembly startupAssembly)
        {
            var projectName = startupAssembly.GetName().Name;
            var applicationBasePath = System.AppContext.BaseDirectory;
            var directoryInfo = new DirectoryInfo(applicationBasePath);
            do
            {
                directoryInfo = directoryInfo.Parent.Parent.Parent.Parent;

                var projectDirectoryInfo = new DirectoryInfo(Path.Combine(directoryInfo.FullName, "Web-App"));
                if (projectDirectoryInfo.Exists)
                {
                    var projectFileInfo = new FileInfo(Path.Combine(projectDirectoryInfo.FullName, projectName, $"{projectName}.csproj"));
                    if (projectFileInfo.Exists)
                    {
                        return Path.Combine(projectDirectoryInfo.FullName, projectName);
                    }
                }
            }
            while (directoryInfo.Parent != null);

            throw new Exception($"Project root could not be located using the application root {applicationBasePath}.");
        }
    }
}