diff --git a/src/Orchard.Tests/Orchard.Framework.Tests.csproj b/src/Orchard.Tests/Orchard.Framework.Tests.csproj
index 80f4694e4..d37fa44fe 100644
--- a/src/Orchard.Tests/Orchard.Framework.Tests.csproj
+++ b/src/Orchard.Tests/Orchard.Framework.Tests.csproj
@@ -209,6 +209,7 @@
     <Compile Include="Mvc\Html\HtmlHelperExtensionsTests.cs" />
     <Compile Include="Mvc\Routes\ShellRouteTests.cs" />
     <Compile Include="Mvc\Routes\UrlPrefixTests.cs" />
+    <Compile Include="Stubs\StubVirtualPathProvider.cs" />
     <Compile Include="Stubs\StubFileSystem.cs" />
     <Compile Include="Stubs\StubAppDataFolder.cs" />
     <Compile Include="Stubs\StubVirtualPathMonitor.cs" />
diff --git a/src/Orchard.Tests/Stubs/StubFileSystem.cs b/src/Orchard.Tests/Stubs/StubFileSystem.cs
index 332cef01a..7234b24e0 100644
--- a/src/Orchard.Tests/Stubs/StubFileSystem.cs
+++ b/src/Orchard.Tests/Stubs/StubFileSystem.cs
@@ -22,6 +22,18 @@ namespace Orchard.Tests.Stubs {
 
             public IList<Entry> Entries { get; private set; }
 
+            public IEnumerable<FileEntry> Files {
+                get {
+                    return Entries.OfType<FileEntry>();
+                }
+            }
+
+            public IEnumerable<DirectoryEntry> Directories {
+                get {
+                    return Entries.OfType<DirectoryEntry>();
+                }
+            }
+
             public Entry GetEntry(string name) {
                 if (string.IsNullOrEmpty(name))
                     throw new ArgumentException();
diff --git a/src/Orchard.Tests/Stubs/StubVirtualPathProvider.cs b/src/Orchard.Tests/Stubs/StubVirtualPathProvider.cs
new file mode 100644
index 000000000..89a70f94e
--- /dev/null
+++ b/src/Orchard.Tests/Stubs/StubVirtualPathProvider.cs
@@ -0,0 +1,80 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Orchard.FileSystems.VirtualPath;
+using Orchard.Services;
+
+namespace Orchard.Tests.Stubs {
+    public class StubVirtualPathProvider : IVirtualPathProvider {
+        private readonly StubFileSystem _fileSystem;
+
+        public StubVirtualPathProvider(StubFileSystem fileSystem) {
+            _fileSystem = fileSystem;
+        }
+
+        public StubFileSystem FileSystem {
+            get { return _fileSystem; }
+        }
+
+        private string ToFileSystemPath(string path) {
+            if (path.StartsWith("~/"))
+                return path.Substring(2);
+            if (path.StartsWith("/"))
+                return path.Substring(1);
+            return path;
+        }
+
+        public string Combine(params string[] paths) {
+            return Path.Combine(paths).Replace(Path.DirectorySeparatorChar, '/');
+        }
+
+        public string MapPath(string virtualPath) {
+            throw new NotImplementedException("Mapping to a physical file is not supported in Unit Test with this stub.");
+        }
+
+        public bool FileExists(string virtualPath) {
+            return _fileSystem.GetFileEntry(ToFileSystemPath(virtualPath)) != null;
+        }
+
+        public Stream OpenFile(string virtualPath) {
+            return _fileSystem.OpenFile(ToFileSystemPath(virtualPath));
+        }
+
+        public StreamWriter CreateText(string virtualPath) {
+            return new StreamWriter(_fileSystem.CreateFile(ToFileSystemPath(virtualPath)));
+        }
+
+        public Stream CreateFile(string virtualPath) {
+            return _fileSystem.CreateFile(ToFileSystemPath(virtualPath));
+        }
+
+        public DateTime GetFileLastWriteTimeUtc(string virtualPath) {
+            return _fileSystem.GetFileEntry(ToFileSystemPath(virtualPath)).LastWriteTimeUtc;
+        }
+
+        public bool DirectoryExists(string virtualPath) {
+            return _fileSystem.GetDirectoryEntry(ToFileSystemPath(virtualPath)) != null;
+        }
+
+        public void CreateDirectory(string virtualPath) {
+            _fileSystem.CreateDirectoryEntry(ToFileSystemPath(virtualPath));
+        }
+
+        public string GetDirectoryName(string virtualPath) {
+            return Path.GetDirectoryName(virtualPath);
+        }
+
+        public IEnumerable<string> ListFiles(string path) {
+            return _fileSystem.GetDirectoryEntry(ToFileSystemPath(path))
+                .Files
+                .Select(f => Combine(path, f.Name));
+        }
+
+        public IEnumerable<string> ListDirectories(string path) {
+            return _fileSystem.GetDirectoryEntry(ToFileSystemPath(path))
+                .Directories
+                .Select(f => Combine(path, f.Name));
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Orchard/Environment/Extensions/Loaders/DynamicExtensionLoader.cs b/src/Orchard/Environment/Extensions/Loaders/DynamicExtensionLoader.cs
index bf4c1d4f7..0af81fad4 100644
--- a/src/Orchard/Environment/Extensions/Loaders/DynamicExtensionLoader.cs
+++ b/src/Orchard/Environment/Extensions/Loaders/DynamicExtensionLoader.cs
@@ -107,7 +107,7 @@ namespace Orchard.Environment.Extensions.Loaders {
 
             return new ExtensionProbeEntry {
                 Descriptor = descriptor,
-                LastModificationTimeUtc = File.GetLastWriteTimeUtc(_virtualPathProvider.MapPath(projectPath)),
+                LastModificationTimeUtc = _virtualPathProvider.GetFileLastWriteTimeUtc(projectPath),
                 Loader = this,
                 VirtualPath = projectPath
             };
diff --git a/src/Orchard/FileSystems/VirtualPath/DefaultVirtualPathProvider.cs b/src/Orchard/FileSystems/VirtualPath/DefaultVirtualPathProvider.cs
index 0883058ea..3313a4ff0 100644
--- a/src/Orchard/FileSystems/VirtualPath/DefaultVirtualPathProvider.cs
+++ b/src/Orchard/FileSystems/VirtualPath/DefaultVirtualPathProvider.cs
@@ -30,6 +30,10 @@ namespace Orchard.FileSystems.VirtualPath {
             return File.CreateText(MapPath(virtualPath));
         }
 
+        public Stream CreateFile(string virtualPath) {
+            return File.Create(MapPath(virtualPath));
+        }
+
         public DateTime GetFileLastWriteTimeUtc(string virtualPath) {
             return File.GetLastWriteTimeUtc(MapPath(virtualPath));
         }
diff --git a/src/Orchard/FileSystems/VirtualPath/IVirtualPathProvider.cs b/src/Orchard/FileSystems/VirtualPath/IVirtualPathProvider.cs
index 2fa00229f..6b012cd75 100644
--- a/src/Orchard/FileSystems/VirtualPath/IVirtualPathProvider.cs
+++ b/src/Orchard/FileSystems/VirtualPath/IVirtualPathProvider.cs
@@ -11,6 +11,7 @@ namespace Orchard.FileSystems.VirtualPath {
         bool FileExists(string virtualPath);
         Stream OpenFile(string virtualPath);
         StreamWriter CreateText(string virtualPath);
+        Stream CreateFile(string virtualPath);
         DateTime GetFileLastWriteTimeUtc(string virtualPath);
 
         bool DirectoryExists(string virtualPath);