Adding support for disabling Owin (with its standard appSettings config), and disabling it for Specs. This allows Specflow tests to be run, without Owin (since Owin prevented those tests from running, it requiring integrated pipeline that is not available when self-hosting through HttpRuntime).

src/Orchard.Specs/Hosting/Orchard.Web/Web.config

@@ -23,7 +23,7 @@
     <add key="webpages:Enabled" value="false" />
     <add key="webpages:Version" value="3.0.0.0"/>
     <add key="log4net.Config" value="Config\log4net.config" />
-    <add key="owin:AppStartup" value="Orchard.Owin.Startup, Orchard.Framework" />
+    <add key="owin:AutomaticAppStartup" value="false" />
   </appSettings>
 
   <system.web.webPages.razor>

src/Orchard.Specs/Hosting/Simple.Web/Web.config

@@ -25,6 +25,7 @@
 
   <appSettings>
     <add key="webpages:Enabled" value="false" />
+    <add key="owin:AutomaticAppStartup" value="false" />
   </appSettings>
 
 

src/Orchard/Mvc/Routes/ShellRoute.cs

@@ -166,7 +166,8 @@ namespace Orchard.Mvc.Routes {
                     var environment = context.Items["owin.Environment"] as IDictionary<string, object>;
 
                     if (environment == null) {
-                        throw new ArgumentException("owin.Environment can't be null");
+                        // It seems Owin is disabled by the owin:AutomaticAppStartup=false appSettings configuration.
+                        environment = new Dictionary<string, object>();
                     }
 
                     environment["orchard.Handler"] = new Func<Task>(async () => {