From d422201e016f2836b8e226683e541c1d8270351c Mon Sep 17 00:00:00 2001
From: John Luo <jt.luo@mail.utoronto.ca>
Date: Tue, 12 Jan 2016 00:47:18 -0800
Subject: [PATCH] Elaborating error message when no startup is specified

---
 src/Microsoft.AspNet.Hosting/Startup/StartupLoader.cs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Microsoft.AspNet.Hosting/Startup/StartupLoader.cs b/src/Microsoft.AspNet.Hosting/Startup/StartupLoader.cs
index 1898dd818a..c77cbced34 100644
--- a/src/Microsoft.AspNet.Hosting/Startup/StartupLoader.cs
+++ b/src/Microsoft.AspNet.Hosting/Startup/StartupLoader.cs
@@ -43,7 +43,10 @@ namespace Microsoft.AspNet.Hosting.Startup
             var environmentName = _hostingEnv.EnvironmentName;
             if (string.IsNullOrEmpty(startupAssemblyName))
             {
-                throw new ArgumentException("Value cannot be null or empty.", nameof(startupAssemblyName));
+                throw new ArgumentException(
+                    string.Format("A startup method, startup type or startup assembly is required. If specifying an assembly, '{0}' cannot be null or empty.", 
+                    nameof(startupAssemblyName)), 
+                    nameof(startupAssemblyName));
             }
 
             var assembly = Assembly.Load(new AssemblyName(startupAssemblyName));