fix #163

src/MBrace.Runtime/Store/FileSystemStore.fs

@@ -18,18 +18,20 @@ type FileSystemStore private (rootPath : string, defaultDirectory : string) =
     [<DataMember(Name = "RootPath")>]
     let rootPath = rootPath
 
-    let normalize (path : string) =
+    let normalize defaultDirectory (path : string) =
         if Path.IsPathRooted path then
             let nf = Path.GetFullPath path
             if nf.StartsWith rootPath then nf
             else
                 let msg = sprintf "invalid path '%O'." path
                 raise <| new FormatException(msg)
         else
-            Path.Combine(rootPath, path) |> Path.GetFullPath
+            Path.Combine(defaultDirectory, path) |> Path.GetFullPath
 
     [<DataMember(Name = "DefaultDirectory")>]
-    let defaultDirectory = normalize defaultDirectory
+    let defaultDirectory = normalize rootPath defaultDirectory
+
+    let normalize p = normalize defaultDirectory p
 
     // IOException will be signifies attempt to perform concurrent writes of file.
     // An exception to this rule is FileNotFoundException, which is a subtype of IOException.

tests/MBrace.Core.Tests/StoreTests/CloudFileStoreTests.fs

@@ -336,6 +336,16 @@ type ``CloudFileStore Tests`` (parallelismFactor : int) as self =
     //  Section 2. FileStore via MBrace runtime
     //
 
+
+    [<Test>]
+    member __.``2. MBrace : relative file paths should always give same absolute`` () = 
+        cloud {
+            let path = Path.GetRandomFileName()
+            let! cf = CloudFile.WriteAllText(path, "text")
+            let! fullPath = CloudPath.GetFullPath path
+            cf.Path |> shouldEqual fullPath
+        } |> runOnCloud
+
     [<Test>]
     member __.``2. MBrace : PersistedValue - simple`` () = 
         let ref = runOnCloud <| PersistedValue.New 42