Using xUnit Theory Member Data with F#
1 minute read
I’ve been using an introductory book on machine learning as an excuse to start cuddling up to F# again, after letting my skills deteriorate. I’m adding unit tests into the mix with the book materials, using FsUnit with xUnit. In doing so, I struggled a bit to get a Theory based on member data working correctly.
I wasn’t able to turn much up in a few searches, so I wanted to capture it here, lest I forget again in the future. The basic structure that worked for me was:
namespace MachineLearningBook.SpamDetector.UnitTests
module DocumentTests =
open FSharp.Reflection
open MachineLearningBook.SpamDetector
open Xunit
open FsUnit.Xunit
type ``Parsing a DocType should produce the expected results`` () =
static member DocTypeNameData
with get() =
FSharpType.GetUnionCases typeof<Document.DocType>
|> Seq.map (fun case -> [| case.Name |])
[<Theory>]
[<MemberData("DocTypeNameData")>]
member verify.``Exact DocTypes can be parsed`` (docTypeName:string) =
let result = Document.DocType.parse docTypeName
result.IsSome |> should be True
result.Value.ToString() |> should equal docTypeName
Hopefully, that helps someone (or future me) to avoid some pain.
Feedback is welcome. Let me know what you think of this article on Twitter @jesse_squire or leave a comment below.
Please keep comments respectful and relevant. Off-topic and inappropriate comments are likely to be removed.
Please see our Community Guidelines for more information.