Adds IUmbracoBuilder to build the config so it's easier to split apart, ensures background tasks don't run in integration tests, uses a custom CoreRuntime to ensure we use SimpleMainDom, re-wires the UmbracoWebApplicationFactory so that duplicate Hosts are not running at the same time, fixes issues with overriding/shadowing, uses RAMDirectory in lucene for tests, fixes CoreRuntime's events that we're moved incorrectly and not backwards compat, adds new real non static events which we can use in integration tests to install the DB before the runtime state is calculated

src/Umbraco.Web.Common/Extensions/UmbracoCoreServiceCollectionExtensions.cs

@@ -178,6 +178,31 @@ namespace Umbraco.Extensions
             IRequestCache requestCache,
             ILoggingConfiguration loggingConfiguration,
             out IFactory factory)
+            => services.AddUmbracoCore(webHostEnvironment, umbContainer, entryAssembly, requestCache, loggingConfiguration, GetCoreRuntime, out factory);
+
+        /// <summary>
+        /// Adds the Umbraco Back Core requirements
+        /// </summary>
+        /// <param name="services"></param>
+        /// <param name="webHostEnvironment"></param>
+        /// <param name="umbContainer"></param>
+        /// <param name="entryAssembly"></param>
+        /// <param name="requestCache"></param>
+        /// <param name="httpContextAccessor"></param>
+        /// <param name="loggingConfiguration"></param>
+        /// <param name="getRuntime">Delegate to create an <see cref="IRuntime"/></param>
+        /// <param name="factory"></param>
+        /// <returns></returns>
+        public static IServiceCollection AddUmbracoCore(
+            this IServiceCollection services,
+            IWebHostEnvironment webHostEnvironment,
+            IRegister umbContainer,
+            Assembly entryAssembly,
+            IRequestCache requestCache,
+            ILoggingConfiguration loggingConfiguration,
+            // TODO: Yep that's extremely ugly
+            Func<Configs, IUmbracoVersion, IIOHelper, Core.Logging.ILogger, IProfiler, Core.Hosting.IHostingEnvironment, IBackOfficeInfo, ITypeFinder, IRequestCache, IDbProviderFactoryCreator, IRuntime> getRuntime,
+            out IFactory factory)
         {
             if (services is null) throw new ArgumentNullException(nameof(services));
             var container = umbContainer;
@@ -216,7 +241,7 @@ namespace Umbraco.Extensions
             var umbracoVersion = new UmbracoVersion(globalSettings);
             var typeFinder = CreateTypeFinder(logger, profiler, webHostEnvironment, entryAssembly, configs.TypeFinder());
 
-            var coreRuntime = GetCoreRuntime(
+            var runtime = getRuntime(
                 configs,
                 umbracoVersion,
                 ioHelper,
@@ -228,7 +253,7 @@ namespace Umbraco.Extensions
                 requestCache,
                 dbProviderFactoryCreator);
 
-            factory = coreRuntime.Configure(container);
+            factory = runtime.Configure(container);
 
             return services;
         }