Added an extension method for C# to convert an FSharpOption into a Result

src/Chessie/ErrorHandling.fs

@@ -361,7 +361,12 @@ type ResultExtensions () =
     /// Otherwise the exisiting error messages are propagated.
     [<Extension>]
     static member inline Join (this: Result<'TOuter, 'TMessage>, inner: Result<'TInner, 'TMessage>, _outerKeySelector: Func<'TOuter,'TKey>, _innerKeySelector: Func<'TInner, 'TKey>, resultSelector: Func<'TOuter, 'TInner, 'TResult>) =
-        let curry func = fun a -> fun b -> func (a, b)
+        let curry func = fun a b -> func (a, b)
         curry resultSelector.Invoke
         <!> this 
-        <*> inner
+        <*> inner
+
+    /// Converts an option into a Result.
+    [<Extension>]
+    static member ToResult(this, msg) =
+        this |> failIfNone msg

tests/Chessie.CSharp.Test/ExtensionsTests.cs

@@ -1,6 +1,7 @@
 using System;
 using Chessie.ErrorHandling;
 using Chessie.ErrorHandling.CSharp;
+using Microsoft.FSharp.Core;
 using NUnit.Framework;
 
 namespace Chessie.CSharp.Test
@@ -58,5 +59,29 @@ from c in r3
                 ifSuccess: (s, _) => Assert.Fail("should fail"),
                 ifFailure: list => Assert.That(list, Is.EquivalentTo(new[] { "fail1" })));
         }
+
+        [Test]
+        public void ToResultOnSomeShouldSucceed()
+        {
+            var opt = FSharpOption<int>.Some(42);
+            var result = opt.ToResult("error");
+            result.Match(
+                ifSuccess: (x, msgs) =>
+                {
+                    Assert.AreEqual(42, x);
+                    Assert.That(msgs, Is.Empty);
+                },
+                ifFailure: errs => Assert.Fail());
+        }
+
+        [Test]
+        public void ToResultOnNoneShoulFail()
+        {
+            var opt = FSharpOption<int>.None;
+            var result = opt.ToResult("error");
+            result.Match(
+                ifSuccess: (x, _) => Assert.Fail(),
+                ifFailure: errs => Assert.That(errs, Is.EquivalentTo(new[] {"error"})));
+        }
     }
 }