Merge pull request #6 from insurello/fromTeeTask

Add fromUnitTask helper

Author: stoft

src/Insurello.AsyncExtra.Tests/AsyncExtraTests.fs

@@ -1,11 +1,14 @@
 module AsyncExtraTests
 
+open System.Threading
+open System.Threading.Tasks
 open Insurello.AsyncExtra
 open Expecto
 
 [<Tests>]
 let tests =
-    testList "Sequence tests"
+    testList
+        "Sequence tests"
         [ testAsync "should return values in same order as given tasks" {
               let dummyAsync: int -> AsyncResult<int, string> = Ok >> AsyncResult.fromResult
 
@@ -15,6 +18,7 @@ let tests =
                   [ (dummyAsync 1)
                     (dummyAsync 2)
                     (dummyAsync 3) ]
+
               let! actual = AsyncResult.sequence input
               Expect.equal actual expected "should equal"
           }
@@ -37,3 +41,57 @@ let tests =
               let! _actual = AsyncResult.sequence input
               Expect.equal orderRun expectedOkValue "Should be run in same order"
           } ]
+
+[<Tests>]
+let taskTests =
+    testList
+        "Task tests"
+        [ testList
+            "fromUnitTask"
+              [ testAsync "should convert from Task to AsyncResult" {
+                    let source = new CancellationTokenSource()
+                    let input: Task = Task.Delay(0, source.Token)
+
+                    let expectedValue = Ok()
+
+                    let! actual = AsyncResult.fromUnitTask input
+
+                    Expect.equal actual expectedValue "Should be equal"
+                }
+                testAsync "failing Task should result in Error" {
+                    let source = new CancellationTokenSource()
+                    let input: Task = Task.Delay(1000, source.Token)
+                    let expectedValue = Error "A task was canceled."
+
+                    source.Cancel()
+
+                    let! actual = AsyncResult.fromUnitTask input
+
+                    Expect.equal actual expectedValue "Should be equal"
+                } ]
+          testList
+              "fromTask"
+              [ testAsync "should convert from Task<string> to AsyncResult" {
+                    let input =
+                        Async.singleton "Hello" |> Async.StartAsTask
+
+                    let expectedValue = Ok "Hello"
+
+                    let! actual = AsyncResult.fromTask input
+
+                    Expect.equal actual expectedValue "Should be equal"
+                }
+                testAsync "fromTask failing Task should result in Error" {
+
+                    let input =
+                        Async.singleton "Hello"
+                        |> Async.map (fun _ -> failwith "boom")
+                        |> Async.StartAsTask
+
+                    let expectedValue =
+                        Error "One or more errors occurred. (boom)"
+
+                    let! actual = AsyncResult.fromTask input
+
+                    Expect.equal actual expectedValue "Should be equal"
+                } ] ]

src/Insurello.AsyncExtra/AsyncExtra.fs

@@ -30,6 +30,15 @@ module AsyncResult =
                 | Choice1Of2 response -> Ok response
                 | Choice2Of2 exn -> Error exn.Message)
 
+    let fromUnitTask: System.Threading.Tasks.Task -> AsyncResult<unit, string> =
+        fun task ->
+            task
+            |> Async.AwaitTask
+            |> Async.Catch
+            |> Async.map (function
+                | Choice1Of2 response -> Ok response
+                | Choice2Of2 exn -> Error exn.Message)
+
     let map: ('x -> 'y) -> AsyncResult<'x, 'err> -> AsyncResult<'y, 'err> =
         fun f asyncResultX -> Async.map (Result.map f) asyncResultX