diff --git a/src/Microsoft.AspNet.StaticFiles/DefaultFilesExtensions.cs b/src/Microsoft.AspNet.StaticFiles/DefaultFilesExtensions.cs
index 2f29be25ac..0ea6c3a8f4 100644
--- a/src/Microsoft.AspNet.StaticFiles/DefaultFilesExtensions.cs
+++ b/src/Microsoft.AspNet.StaticFiles/DefaultFilesExtensions.cs
@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.StaticFiles;
 
@@ -17,7 +16,7 @@ namespace Microsoft.AspNet.Builder
         /// </summary>
         /// <param name="builder"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDefaultFiles(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseDefaultFiles([NotNull] this IApplicationBuilder builder)
         {
             return builder.UseDefaultFiles(new DefaultFilesOptions());
         }
@@ -28,9 +27,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="requestPath">The relative request path and physical path.</param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDefaultFiles(this IApplicationBuilder builder, string requestPath)
+        public static IApplicationBuilder UseDefaultFiles([NotNull] this IApplicationBuilder builder, [NotNull] string requestPath)
         {
-            return UseDefaultFiles(builder, new DefaultFilesOptions() { RequestPath = new PathString(requestPath) });
+            return builder.UseDefaultFiles(new DefaultFilesOptions() { RequestPath = new PathString(requestPath) });
         }
 
         /// <summary>
@@ -39,14 +38,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDefaultFiles(this IApplicationBuilder builder, DefaultFilesOptions options)
+        public static IApplicationBuilder UseDefaultFiles([NotNull] this IApplicationBuilder builder, [NotNull] DefaultFilesOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-
-            return builder.Use(next => new DefaultFilesMiddleware(next, options).Invoke);
+            return builder.UseMiddleware<DefaultFilesMiddleware>(options);
         }
     }
 }
\ No newline at end of file
diff --git a/src/Microsoft.AspNet.StaticFiles/DefaultFilesMiddleware.cs b/src/Microsoft.AspNet.StaticFiles/DefaultFilesMiddleware.cs
index 96f6198b07..4cf577c429 100644
--- a/src/Microsoft.AspNet.StaticFiles/DefaultFilesMiddleware.cs
+++ b/src/Microsoft.AspNet.StaticFiles/DefaultFilesMiddleware.cs
@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.FileSystems;
+using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.StaticFiles
@@ -26,19 +27,11 @@ namespace Microsoft.AspNet.StaticFiles
         /// </summary>
         /// <param name="next">The next middleware in the pipeline.</param>
         /// <param name="options">The configuration options for this middleware.</param>
-        public DefaultFilesMiddleware(RequestDelegate next, DefaultFilesOptions options)
+        public DefaultFilesMiddleware([NotNull] RequestDelegate next, [NotNull] IHostingEnvironment hostingEnv, [NotNull] DefaultFilesOptions options)
         {
-            if (next == null)
-            {
-                throw new ArgumentNullException("next");
-            }
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
             if (options.FileSystem == null)
             {
-                options.FileSystem = new PhysicalFileSystem("." + options.RequestPath.Value);
+                options.FileSystem = new PhysicalFileSystem(Helpers.ResolveRootPath(hostingEnv.WebRoot, options.RequestPath));
             }
 
             _next = next;
diff --git a/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserExtensions.cs b/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserExtensions.cs
index dbd83c0970..fe32f39028 100644
--- a/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserExtensions.cs
+++ b/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserExtensions.cs
@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.StaticFiles;
 
@@ -17,7 +16,7 @@ namespace Microsoft.AspNet.Builder
         /// </summary>
         /// <param name="builder"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDirectoryBrowser(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseDirectoryBrowser([NotNull] this IApplicationBuilder builder)
         {
             return builder.UseDirectoryBrowser(new DirectoryBrowserOptions());
         }
@@ -28,9 +27,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="requestPath">The relative request path and physical path.</param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDirectoryBrowser(this IApplicationBuilder builder, string requestPath)
+        public static IApplicationBuilder UseDirectoryBrowser([NotNull] this IApplicationBuilder builder, [NotNull] string requestPath)
         {
-            return UseDirectoryBrowser(builder, new DirectoryBrowserOptions() { RequestPath = new PathString(requestPath) });
+            return builder.UseDirectoryBrowser(new DirectoryBrowserOptions() { RequestPath = new PathString(requestPath) });
         }
 
         /// <summary>
@@ -39,14 +38,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDirectoryBrowser(this IApplicationBuilder builder, DirectoryBrowserOptions options)
+        public static IApplicationBuilder UseDirectoryBrowser([NotNull] this IApplicationBuilder builder, [NotNull] DirectoryBrowserOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-
-            return builder.Use(next => new DirectoryBrowserMiddleware(next, options).Invoke);
+            return builder.UseMiddleware<DirectoryBrowserMiddleware>(options);
         }
     }
 }
\ No newline at end of file
diff --git a/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserMiddleware.cs b/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserMiddleware.cs
index ba4b336163..ba61682631 100644
--- a/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserMiddleware.cs
+++ b/src/Microsoft.AspNet.StaticFiles/DirectoryBrowserMiddleware.cs
@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.FileSystems;
+using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.StaticFiles
@@ -24,23 +25,15 @@ namespace Microsoft.AspNet.StaticFiles
         /// </summary>
         /// <param name="next">The next middleware in the pipeline.</param>
         /// <param name="options">The configuration for this middleware.</param>
-        public DirectoryBrowserMiddleware(RequestDelegate next, DirectoryBrowserOptions options)
+        public DirectoryBrowserMiddleware([NotNull] RequestDelegate next, [NotNull] IHostingEnvironment hostingEnv, [NotNull] DirectoryBrowserOptions options)
         {
-            if (next == null)
-            {
-                throw new ArgumentNullException("next");
-            }
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
             if (options.Formatter == null)
             {
                 throw new ArgumentException(Resources.Args_NoFormatter);
             }
             if (options.FileSystem == null)
             {
-                options.FileSystem = new PhysicalFileSystem("." + options.RequestPath.Value);
+                options.FileSystem = new PhysicalFileSystem(Helpers.ResolveRootPath(hostingEnv.WebRoot, options.RequestPath));
             }
 
             _next = next;
diff --git a/src/Microsoft.AspNet.StaticFiles/FileServerExtensions.cs b/src/Microsoft.AspNet.StaticFiles/FileServerExtensions.cs
index d7fe812218..9de67fc531 100644
--- a/src/Microsoft.AspNet.StaticFiles/FileServerExtensions.cs
+++ b/src/Microsoft.AspNet.StaticFiles/FileServerExtensions.cs
@@ -18,9 +18,9 @@ namespace Microsoft.AspNet.Builder
         /// </summary>
         /// <param name="builder"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseFileServer(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseFileServer([NotNull] this IApplicationBuilder builder)
         {
-            return UseFileServer(builder, new FileServerOptions());
+            return builder.UseFileServer(new FileServerOptions());
         }
 
         /// <summary>
@@ -29,9 +29,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="enableDirectoryBrowsing">Should directory browsing be enabled?</param>
         /// <returns></returns>
-        public static IApplicationBuilder UseFileServer(this IApplicationBuilder builder, bool enableDirectoryBrowsing)
+        public static IApplicationBuilder UseFileServer([NotNull] this IApplicationBuilder builder, bool enableDirectoryBrowsing)
         {
-            return UseFileServer(builder, new FileServerOptions() { EnableDirectoryBrowsing = enableDirectoryBrowsing });
+            return builder.UseFileServer(new FileServerOptions() { EnableDirectoryBrowsing = enableDirectoryBrowsing });
         }
 
         /// <summary>
@@ -40,9 +40,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="requestPath">The relative request path and physical path.</param>
         /// <returns></returns>
-        public static IApplicationBuilder UseFileServer(this IApplicationBuilder builder, string requestPath)
+        public static IApplicationBuilder UseFileServer([NotNull] this IApplicationBuilder builder, [NotNull] string requestPath)
         {
-            return UseFileServer(builder, new FileServerOptions() { RequestPath = new PathString(requestPath) });
+            return builder.UseFileServer(new FileServerOptions() { RequestPath = new PathString(requestPath) });
         }
 
         /// <summary>
@@ -51,7 +51,7 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseFileServer(this IApplicationBuilder builder, FileServerOptions options)
+        public static IApplicationBuilder UseFileServer([NotNull] this IApplicationBuilder builder, [NotNull] FileServerOptions options)
         {
             if (options == null)
             {
diff --git a/src/Microsoft.AspNet.StaticFiles/Helpers.cs b/src/Microsoft.AspNet.StaticFiles/Helpers.cs
index eeb867b07d..efee663776 100644
--- a/src/Microsoft.AspNet.StaticFiles/Helpers.cs
+++ b/src/Microsoft.AspNet.StaticFiles/Helpers.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Globalization;
+using System.IO;
 using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.StaticFiles
@@ -49,5 +50,10 @@ namespace Microsoft.AspNet.StaticFiles
         {
             return DateTime.TryParseExact(dateString, Constants.HttpDateFormat, CultureInfo.InvariantCulture, DateTimeStyles.None, out parsedDate);
         }
+
+        internal static string ResolveRootPath(string webRoot, PathString path)
+        {
+            return Path.GetFullPath(Path.Combine(webRoot, path.Value ?? string.Empty));
+        }
     }
 }
diff --git a/src/Microsoft.AspNet.StaticFiles/IHostingEnvironment.cs b/src/Microsoft.AspNet.StaticFiles/IHostingEnvironment.cs
new file mode 100644
index 0000000000..d510d0ba23
--- /dev/null
+++ b/src/Microsoft.AspNet.StaticFiles/IHostingEnvironment.cs
@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Framework.Runtime;
+
+namespace Microsoft.AspNet.Hosting
+{
+    [AssemblyNeutral]
+    public interface IHostingEnvironment
+    {
+        string EnvironmentName { get; }
+
+        string WebRoot { get; }
+    }
+}
\ No newline at end of file
diff --git a/src/Microsoft.AspNet.StaticFiles/NotNullAttribute.cs b/src/Microsoft.AspNet.StaticFiles/NotNullAttribute.cs
new file mode 100644
index 0000000000..bc879f17b6
--- /dev/null
+++ b/src/Microsoft.AspNet.StaticFiles/NotNullAttribute.cs
@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNet.StaticFiles
+{
+    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false)]
+    internal sealed class NotNullAttribute : Attribute
+    {
+    }
+}
\ No newline at end of file
diff --git a/src/Microsoft.AspNet.StaticFiles/SendFileExtensions.cs b/src/Microsoft.AspNet.StaticFiles/SendFileExtensions.cs
index 2248ea2053..5ec72f4c68 100644
--- a/src/Microsoft.AspNet.StaticFiles/SendFileExtensions.cs
+++ b/src/Microsoft.AspNet.StaticFiles/SendFileExtensions.cs
@@ -17,13 +17,8 @@ namespace Microsoft.AspNet.StaticFiles
         /// </summary>
         /// <param name="builder"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseSendFileFallback(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseSendFileFallback([NotNull] this IApplicationBuilder builder)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-
             /* TODO builder.GetItem(typeof(ISendFile))
 
             // Check for advertised support
@@ -35,7 +30,7 @@ namespace Microsoft.AspNet.StaticFiles
             // Otherwise, insert a fallback SendFile middleware and advertise support
             SetSendFileCapability(builder.Properties);
              */
-            return builder.Use(next => new SendFileMiddleware(next).Invoke);
+            return builder.UseMiddleware<SendFileMiddleware>();
         }
 
         private static bool IsSendFileSupported(IDictionary<string, object> properties)
diff --git a/src/Microsoft.AspNet.StaticFiles/SendFileMiddleware.cs b/src/Microsoft.AspNet.StaticFiles/SendFileMiddleware.cs
index 92b15fc92b..8351dcd3a3 100644
--- a/src/Microsoft.AspNet.StaticFiles/SendFileMiddleware.cs
+++ b/src/Microsoft.AspNet.StaticFiles/SendFileMiddleware.cs
@@ -25,13 +25,8 @@ namespace Microsoft.AspNet.StaticFiles
         /// Creates a new instance of the SendFileMiddleware.
         /// </summary>
         /// <param name="next">The next middleware in the pipeline.</param>
-        public SendFileMiddleware(RequestDelegate next)
+        public SendFileMiddleware([NotNull] RequestDelegate next)
         {
-            if (next == null)
-            {
-                throw new ArgumentNullException("next");
-            }
-
             _next = next;
         }
 
diff --git a/src/Microsoft.AspNet.StaticFiles/SendFileResponseExtensions.cs b/src/Microsoft.AspNet.StaticFiles/SendFileResponseExtensions.cs
index 41edeae38b..8207505b4a 100644
--- a/src/Microsoft.AspNet.StaticFiles/SendFileResponseExtensions.cs
+++ b/src/Microsoft.AspNet.StaticFiles/SendFileResponseExtensions.cs
@@ -19,12 +19,8 @@ namespace Microsoft.AspNet.StaticFiles
         /// </summary>
         /// <param name="response"></param>
         /// <returns>True if sendfile.SendAsync is defined in the environment.</returns>
-        public static bool SupportsSendFile(this HttpResponse response)
+        public static bool SupportsSendFile([NotNull] this HttpResponse response)
         {
-            if (response == null)
-            {
-                throw new ArgumentNullException("response");
-            }
             return response.HttpContext.GetFeature<IHttpSendFileFeature>() != null;
         }
 
@@ -34,12 +30,8 @@ namespace Microsoft.AspNet.StaticFiles
         /// <param name="response"></param>
         /// <param name="fileName"></param>
         /// <returns></returns>
-        public static Task SendFileAsync(this HttpResponse response, string fileName)
+        public static Task SendFileAsync([NotNull] this HttpResponse response, [NotNull] string fileName)
         {
-            if (response == null)
-            {
-                throw new ArgumentNullException("response");
-            }
             return response.SendFileAsync(fileName, 0, null, CancellationToken.None);
         }
 
@@ -52,12 +44,8 @@ namespace Microsoft.AspNet.StaticFiles
         /// <param name="count">The number of types to send, or null to send the remainder of the file.</param>
         /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public static Task SendFileAsync(this HttpResponse response, string fileName, long offset, long? count, CancellationToken cancellationToken)
+        public static Task SendFileAsync([NotNull] this HttpResponse response, [NotNull] string fileName, long offset, long? count, CancellationToken cancellationToken)
         {
-            if (response == null)
-            {
-                throw new ArgumentNullException("response");
-            }
             var sendFile = response.HttpContext.GetFeature<IHttpSendFileFeature>();
             if (sendFile == null)
             {
diff --git a/src/Microsoft.AspNet.StaticFiles/StaticFileExtensions.cs b/src/Microsoft.AspNet.StaticFiles/StaticFileExtensions.cs
index a514870f08..0a95e1f36e 100644
--- a/src/Microsoft.AspNet.StaticFiles/StaticFileExtensions.cs
+++ b/src/Microsoft.AspNet.StaticFiles/StaticFileExtensions.cs
@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.StaticFiles;
 
@@ -17,9 +16,9 @@ namespace Microsoft.AspNet.Builder
         /// </summary>
         /// <param name="builder"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseStaticFiles(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseStaticFiles([NotNull] this IApplicationBuilder builder)
         {
-            return UseStaticFiles(builder, new StaticFileOptions());
+            return builder.UseStaticFiles(new StaticFileOptions());
         }
 
         /// <summary>
@@ -28,9 +27,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="requestPath">The relative request path and physical path.</param>
         /// <returns></returns>
-        public static IApplicationBuilder UseStaticFiles(this IApplicationBuilder builder, string requestPath)
+        public static IApplicationBuilder UseStaticFiles([NotNull] this IApplicationBuilder builder, [NotNull] string requestPath)
         {
-            return UseStaticFiles(builder, new StaticFileOptions() { RequestPath = new PathString(requestPath) });
+            return builder.UseStaticFiles(new StaticFileOptions() { RequestPath = new PathString(requestPath) });
         }
 
         /// <summary>
@@ -39,13 +38,9 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseStaticFiles(this IApplicationBuilder builder, StaticFileOptions options)
+        public static IApplicationBuilder UseStaticFiles([NotNull] this IApplicationBuilder builder, [NotNull] StaticFileOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-            return builder.Use(next => new StaticFileMiddleware(next, options).Invoke);
+            return builder.UseMiddleware<StaticFileMiddleware>(options);
         }
     }
 }
diff --git a/src/Microsoft.AspNet.StaticFiles/StaticFileMiddleware.cs b/src/Microsoft.AspNet.StaticFiles/StaticFileMiddleware.cs
index 7a9a3e8967..e55ae49e6a 100644
--- a/src/Microsoft.AspNet.StaticFiles/StaticFileMiddleware.cs
+++ b/src/Microsoft.AspNet.StaticFiles/StaticFileMiddleware.cs
@@ -5,6 +5,7 @@ using System;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.FileSystems;
+using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.StaticFiles
@@ -23,23 +24,15 @@ namespace Microsoft.AspNet.StaticFiles
         /// </summary>
         /// <param name="next">The next middleware in the pipeline.</param>
         /// <param name="options">The configuration options.</param>
-        public StaticFileMiddleware(RequestDelegate next, StaticFileOptions options)
+        public StaticFileMiddleware([NotNull] RequestDelegate next, [NotNull] IHostingEnvironment hostingEnv, [NotNull] StaticFileOptions options)
         {
-            if (next == null)
-            {
-                throw new ArgumentNullException("next");
-            }
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
             if (options.ContentTypeProvider == null)
             {
                 throw new ArgumentException(Resources.Args_NoContentTypeProvider);
             }
             if (options.FileSystem == null)
             {
-                options.FileSystem = new PhysicalFileSystem("." + options.RequestPath.Value);
+                options.FileSystem = new PhysicalFileSystem(Helpers.ResolveRootPath(hostingEnv.WebRoot, options.RequestPath));
             }
 
             _next = next;
diff --git a/src/Microsoft.AspNet.StaticFiles/project.json b/src/Microsoft.AspNet.StaticFiles/project.json
index 5ad8ca201e..be56a85d13 100644
--- a/src/Microsoft.AspNet.StaticFiles/project.json
+++ b/src/Microsoft.AspNet.StaticFiles/project.json
@@ -3,7 +3,8 @@
   "dependencies": {
     "Microsoft.AspNet.FileSystems": "1.0.0-*",
     "Microsoft.AspNet.Http": "1.0.0-*",
-    "Microsoft.AspNet.HttpFeature": "1.0.0-*"
+    "Microsoft.AspNet.HttpFeature": "1.0.0-*",
+    "Microsoft.AspNet.RequestContainer": "1.0.0-*"
   },
   "frameworks": {
     "aspnet50": {},
diff --git a/test/Microsoft.AspNet.StaticFiles.Tests/DefaultFilesMiddlewareTests.cs b/test/Microsoft.AspNet.StaticFiles.Tests/DefaultFilesMiddlewareTests.cs
index 5cd549d8ba..bc41dfbfc3 100644
--- a/test/Microsoft.AspNet.StaticFiles.Tests/DefaultFilesMiddlewareTests.cs
+++ b/test/Microsoft.AspNet.StaticFiles.Tests/DefaultFilesMiddlewareTests.cs
@@ -20,8 +20,6 @@ namespace Microsoft.AspNet.StaticFiles
         [Fact]
         public async Task NullArguments()
         {
-            Assert.Throws<ArgumentNullException>(() => TestServer.Create(app => app.UseDefaultFiles((DefaultFilesOptions)null)));
-
             // No exception, default provided
             TestServer.Create(app => app.UseDefaultFiles(new DefaultFilesOptions() { FileSystem = null }));
 
@@ -32,11 +30,11 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("", @"", "/missing.dir")]
+        [InlineData("", @".", "/missing.dir")]
         [InlineData("", @".", "/missing.dir/")]
         [InlineData("/subdir", @".", "/subdir/missing.dir")]
-        [InlineData("/subdir", @"", "/subdir/missing.dir/")]
-        [InlineData("", @"\", "/missing.dir")]
+        [InlineData("/subdir", @".", "/subdir/missing.dir/")]
+        [InlineData("", @".\", "/missing.dir")]
         public async Task NoMatch_PassesThrough(string baseUrl, string baseDir, string requestUrl)
         {
             TestServer server = TestServer.Create(app =>
@@ -44,7 +42,7 @@ namespace Microsoft.AspNet.StaticFiles
                 app.UseDefaultFiles(new DefaultFilesOptions()
                 {
                     RequestPath = new PathString(baseUrl),
-                    FileSystem = new PhysicalFileSystem(baseDir)
+                    FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
                 });
                 app.Run(context => context.Response.WriteAsync(context.Request.Path.Value));
             });
@@ -55,10 +53,8 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("", @"", "/SubFolder/")]
         [InlineData("", @".", "/SubFolder/")]
         [InlineData("", @".\", "/SubFolder/")]
-        [InlineData("", @"SubFolder", "/")]
         [InlineData("", @".\SubFolder", "/")]
         public async Task FoundDirectoryWithDefaultFile_PathModified(string baseUrl, string baseDir, string requestUrl)
         {
@@ -67,7 +63,7 @@ namespace Microsoft.AspNet.StaticFiles
                 app.UseDefaultFiles(new DefaultFilesOptions()
                 {
                     RequestPath = new PathString(baseUrl),
-                    FileSystem = new PhysicalFileSystem(baseDir)
+                    FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
                 });
                 app.Run(context => context.Response.WriteAsync(context.Request.Path.Value));
             });
@@ -78,18 +74,15 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("", @"", "/SubFolder", "")]
         [InlineData("", @".", "/SubFolder", "")]
         [InlineData("", @".\", "/SubFolder", "")]
         [InlineData("", @".\", "/SubFolder", "?a=b")]
-        [InlineData("", @".\", "/SubFolder", "?a=b")]
-        [InlineData("", @".\", "/SubFolder", "?a=b")]
         public async Task NearMatch_RedirectAddSlash(string baseUrl, string baseDir, string requestUrl, string queryString)
         {
             TestServer server = TestServer.Create(app => app.UseDefaultFiles(new DefaultFilesOptions()
             {
                 RequestPath = new PathString(baseUrl),                
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl + queryString).GetAsync();
             
@@ -99,8 +92,8 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("/SubFolder", @"\", "/SubFolder/")]
-        [InlineData("/SubFolder", @"", "/somedir/")]
+        [InlineData("/SubFolder", @".\", "/SubFolder/")]
+        [InlineData("/SubFolder", @".", "/somedir/")]
         [InlineData("", @".\SubFolder", "/")]
         [InlineData("", @".\SubFolder\", "/")]
         public async Task PostDirectory_PassesThrough(string baseUrl, string baseDir, string requestUrl)
@@ -108,7 +101,7 @@ namespace Microsoft.AspNet.StaticFiles
             TestServer server = TestServer.Create(app => app.UseDefaultFiles(new DefaultFilesOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).GetAsync();
 
diff --git a/test/Microsoft.AspNet.StaticFiles.Tests/DirectoryBrowserMiddlewareTests.cs b/test/Microsoft.AspNet.StaticFiles.Tests/DirectoryBrowserMiddlewareTests.cs
index 77042807ab..4f6888be41 100644
--- a/test/Microsoft.AspNet.StaticFiles.Tests/DirectoryBrowserMiddlewareTests.cs
+++ b/test/Microsoft.AspNet.StaticFiles.Tests/DirectoryBrowserMiddlewareTests.cs
@@ -1,8 +1,10 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
 
 using System;
+using System.IO;
 using System.Net;
 using System.Net.Http;
+using System.Reflection;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.FileSystems;
@@ -17,8 +19,7 @@ namespace Microsoft.AspNet.StaticFiles
         [Fact]
         public async Task NullArguments()
         {
-            Assert.Throws<ArgumentNullException>(() => TestServer.Create(app => app.UseDirectoryBrowser((DirectoryBrowserOptions)null)));
-            Assert.Throws<ArgumentException>(() => TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions() { Formatter = null })));
+            Assert.Throws<TargetInvocationException>(() => TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions() { Formatter = null })));
 
             // No exception, default provided
             TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions() { FileSystem = null }));
@@ -30,36 +31,34 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("", @"", "/missing.dir")]
+        [InlineData("", @".", "/missing.dir")]
         [InlineData("", @".", "/missing.dir/")]
         [InlineData("/subdir", @".", "/subdir/missing.dir")]
-        [InlineData("/subdir", @"", "/subdir/missing.dir/")]
-        [InlineData("", @"\", "/missing.dir")]
+        [InlineData("/subdir", @".", "/subdir/missing.dir/")]
+        [InlineData("", @".\", "/missing.dir")]
         public async Task NoMatch_PassesThrough(string baseUrl, string baseDir, string requestUrl)
         {
             TestServer server = TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions()
             {
                 RequestPath = new PathString(baseUrl), 
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).GetAsync();
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
         }
 
         [Theory]
-        [InlineData("", @"", "/")]
         [InlineData("", @".", "/")]
-        [InlineData("", @"", "/SubFolder/")]
         [InlineData("", @".", "/SubFolder/")]
-        [InlineData("/somedir", @"", "/somedir/")]
-        [InlineData("/somedir", @"\", "/somedir/")]
+        [InlineData("/somedir", @".", "/somedir/")]
+        [InlineData("/somedir", @".\", "/somedir/")]
         [InlineData("/somedir", @".", "/somedir/subfolder/")]
         public async Task FoundDirectory_Served(string baseUrl, string baseDir, string requestUrl)
         {
             TestServer server = TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).GetAsync();
 
@@ -70,20 +69,18 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("", @"", "/SubFolder", "")]
         [InlineData("", @".", "/SubFolder", "")]
-        [InlineData("/somedir", @"", "/somedir", "")]
+        [InlineData("/somedir", @".", "/somedir", "")]
         [InlineData("/somedir", @".", "/somedir/subfolder", "")]
-        [InlineData("", @"", "/SubFolder", "?a=b")]
         [InlineData("", @".", "/SubFolder", "?a=b")]
-        [InlineData("/somedir", @"", "/somedir", "?a=b")]
+        [InlineData("/somedir", @".", "/somedir", "?a=b")]
         [InlineData("/somedir", @".", "/somedir/subfolder", "?a=b")]
         public async Task NearMatch_RedirectAddSlash(string baseUrl, string baseDir, string requestUrl, string queryString)
         {
             TestServer server = TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl + queryString).GetAsync();
 
@@ -93,36 +90,32 @@ namespace Microsoft.AspNet.StaticFiles
         }
 
         [Theory]
-        [InlineData("", @"", "/")]
         [InlineData("", @".", "/")]
-        [InlineData("", @"", "/SubFolder/")]
         [InlineData("", @".", "/SubFolder/")]
-        [InlineData("/somedir", @"", "/somedir/")]
+        [InlineData("/somedir", @".", "/somedir/")]
         [InlineData("/somedir", @".", "/somedir/subfolder/")]
         public async Task PostDirectory_PassesThrough(string baseUrl, string baseDir, string requestUrl)
         {
             TestServer server = TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).PostAsync();
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
         }
 
         [Theory]
-        [InlineData("", @"", "/")]
         [InlineData("", @".", "/")]
-        [InlineData("", @"", "/SubFolder/")]
         [InlineData("", @".", "/SubFolder/")]
-        [InlineData("/somedir", @"", "/somedir/")]
+        [InlineData("/somedir", @".", "/somedir/")]
         [InlineData("/somedir", @".", "/somedir/subfolder/")]
         public async Task HeadDirectory_HeadersButNotBodyServed(string baseUrl, string baseDir, string requestUrl)
         {
             TestServer server = TestServer.Create(app => app.UseDirectoryBrowser(new DirectoryBrowserOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).SendAsync("HEAD");
 
diff --git a/test/Microsoft.AspNet.StaticFiles.Tests/StaticFileMiddlewareTests.cs b/test/Microsoft.AspNet.StaticFiles.Tests/StaticFileMiddlewareTests.cs
index 1983b435ff..51f754633f 100644
--- a/test/Microsoft.AspNet.StaticFiles.Tests/StaticFileMiddlewareTests.cs
+++ b/test/Microsoft.AspNet.StaticFiles.Tests/StaticFileMiddlewareTests.cs
@@ -4,6 +4,7 @@ using System;
 using System.IO;
 using System.Net;
 using System.Net.Http;
+using System.Reflection;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.FileSystems;
@@ -18,8 +19,7 @@ namespace Microsoft.AspNet.StaticFiles
         [Fact]
         public async Task NullArguments()
         {
-            Assert.Throws<ArgumentNullException>(() => TestServer.Create(app => app.UseStaticFiles((StaticFileOptions)null)));
-            Assert.Throws<ArgumentException>(() => TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions() { ContentTypeProvider = null })));
+            Assert.Throws<TargetInvocationException>(() => TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions() { ContentTypeProvider = null })));
 
             // No exception, default provided
             TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions() { FileSystem = null }));
@@ -33,20 +33,20 @@ namespace Microsoft.AspNet.StaticFiles
         [Fact]
         public void GivenDirDoesntExist_Throw()
         {
-            Assert.Throws<DirectoryNotFoundException>(() => TestServer.Create(app => app.UseStaticFiles("/ThisDirDoesntExist")));
+            Assert.Throws<TargetInvocationException>(() => TestServer.Create(app => app.UseStaticFiles("/ThisDirDoesntExist")));
         }
 
         [Theory]
         [InlineData("", @".", "/missing.file")]
         [InlineData("/subdir", @".", "/subdir/missing.file")]
-        [InlineData("/missing.file", @"\", "/missing.file")]
-        [InlineData("", @"\", "/xunit.xml")]
+        [InlineData("/missing.file", @".\", "/missing.file")]
+        [InlineData("", @".\", "/xunit.xml")]
         public async Task NoMatch_PassesThrough(string baseUrl, string baseDir, string requestUrl)
         {
             TestServer server = TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).GetAsync();
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
@@ -64,7 +64,7 @@ namespace Microsoft.AspNet.StaticFiles
             TestServer server = TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).GetAsync();
 
@@ -86,7 +86,7 @@ namespace Microsoft.AspNet.StaticFiles
             TestServer server = TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).PostAsync();
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
@@ -104,7 +104,7 @@ namespace Microsoft.AspNet.StaticFiles
             TestServer server = TestServer.Create(app => app.UseStaticFiles(new StaticFileOptions()
             {
                 RequestPath = new PathString(baseUrl),
-                FileSystem = new PhysicalFileSystem(baseDir)
+                FileSystem = new PhysicalFileSystem(Path.Combine(Environment.CurrentDirectory, baseDir))
             }));
             HttpResponseMessage response = await server.CreateRequest(requestUrl).SendAsync("HEAD");