TestServer should not capture startup errors by default

src/Microsoft.AspNet.Hosting.Abstractions/IWebApplicationBuilder.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Hosting.Server;
 using Microsoft.Extensions.Configuration;
@@ -13,6 +14,8 @@ namespace Microsoft.AspNet.Hosting
     {
         IWebApplication Build();
 
+        IDictionary<string, string> Settings { get; }
+
         IWebApplicationBuilder UseConfiguration(IConfiguration configuration);
 
         IWebApplicationBuilder UseServer(IServerFactory factory);

src/Microsoft.AspNet.Hosting/WebApplicationBuilder.cs

@@ -17,7 +17,6 @@ using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.PlatformAbstractions;
-using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.AspNet.Hosting
 {
@@ -38,7 +37,7 @@ namespace Microsoft.AspNet.Hosting
         // Only one of these should be set
         private IServerFactory _serverFactory;
 
-        private Dictionary<string, string> _settings = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        private IDictionary<string, string> _settings = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
 
         public WebApplicationBuilder()
         {
@@ -46,6 +45,14 @@ namespace Microsoft.AspNet.Hosting
             _loggerFactory = new LoggerFactory();
         }
 
+        public IDictionary<string, string> Settings
+        {
+            get
+            {
+                return _settings;
+            }
+        }
+
         public IWebApplicationBuilder UseSetting(string key, string value)
         {
             _settings[key] = value;

src/Microsoft.AspNet.TestHost/TestServer.cs

@@ -22,6 +22,11 @@ namespace Microsoft.AspNet.TestHost
 
         public TestServer(IWebApplicationBuilder builder)
         {
+            if (!builder.Settings.ContainsKey(WebApplicationDefaults.CaptureStartupErrorsKey))
+            {
+                builder.UseCaptureStartupErrors(false);
+            }
+
             var application = builder.UseServer(this).Build();
             application.Start();
             _appInstance = application;

test/Microsoft.AspNet.TestHost.Tests/TestServerTests.cs

@@ -30,6 +30,34 @@ namespace Microsoft.AspNet.TestHost
             new TestServer(new WebApplicationBuilder().Configure(app => { }));
         }
 
+
+        [Fact]
+        public void DoesNotCaptureStartupErrorsByDefault()
+        {
+            var builder = new WebApplicationBuilder()
+                .Configure(app =>
+                {
+                    throw new InvalidOperationException();
+                });
+
+            Assert.Throws<InvalidOperationException>(() => new TestServer(builder));
+        }
+
+
+        [Fact]
+        public void CaptureStartupErrorsSettingPreserved()
+        {
+            var builder = new WebApplicationBuilder()
+                .UseCaptureStartupErrors(true)
+                .Configure(app =>
+                {
+                    throw new InvalidOperationException();
+                });
+
+            // Does not throw
+            new TestServer(builder);
+        }
+
         [Fact]
         public void ApplicationServicesAvailableFromTestServer()
         {