How to write async unit test method in F #

Question

How to write async validation method in F #?

I refer to the following code :

[TestMethod]
public async Task CorrectlyFailingTest()
{
  await SystemUnderTest.FailAsync();
}

This is my unsuccessful attempt:

[<Test>]
let ``Correctly failing test``() = async {

        SystemUnderTest.FailAsync() | Async.RunSynchronously
    }

Answer 1

So, after a little research, it turns out that this is more complicated than it should be. https://github.com/nunit/nunit/issues/34

It was said that a workaround was mentioned. It seems a little lame, but it seems like declaring the delegate of the task outside of membership and using it is a viable job.

Examples mentioned in the stream:

open System.Threading.Tasks
open System.Runtime.CompilerServices

let toTask computation : Task = Async.StartAsTask computation :> _

[<Test>]
[<AsyncStateMachine(typeof<Task>)>]
member x.``Test``() = toTask <| async {
    do! asyncStuff()
}

and

open System.Threading.Tasks
open NUnit.Framework

let toAsyncTestDelegate computation = 
    new AsyncTestDelegate(fun () -> Async.StartAsTask computation :> Task)

[<Test>]
member x.``TestWithNUnit``() = 
    Assert.ThrowsAsync<InvalidOperationException>(asyncStuff 123 |> toAsyncTestDelegate)
    |> ignore

[<Test>]
member x.``TestWithFsUnit``() = 
    asyncStuff 123 
    |> toAsyncTestDelegate
    |> should throw typeof<InvalidOperationException>

XUnit had a similar problem and came up with a solution: https://github.com/xunit/xunit/issues/955

So you have to do this in xunit

[<Fact>]
let ``my async test``() =
  async {
    let! x = someAsyncCall()
    AssertOnX
  }

, .

Answer 2

open Xunit

[<Fact>]
let ``my async test``() =
  async {
    do! Async.AwaitTask(someAsyncCall())|> Async.Ignore
    AssertOnX
  }