open System.IO

open Ploeh.AutoFixture

open Xunit

open Xunit.Extensions

​

/// Read lines from a text reader then dispose

let streamLines (reader : TextReader) = 

    reader |> Seq.unfold (fun r ->

        match r.ReadLine() with

        | null -> r.Dispose(); None

        | str -> Some(str, r))

​

let ``Read lines then dispose`` (expected : string []) = 

    let disposed = ref false

    let readLineCallNum = ref 0

    let textReader = {

        new TextReader() with

            member x.Dispose(disposing) = 

                disposed := true

                base.Dispose(disposing)

            member x.ReadLine() = 

                readLineCallNum := !readLineCallNum + 1

                match !readLineCallNum with

                | n when n < expected.Length + 1 -> expected.[n - 1]

                | _ -> null }

​

    let actual = streamLines (textReader) |> Seq.toArray

    Assert.Equal<string>(expected, actual)

    Assert.True !disposed

​

​

``Read lines then dispose``(Fixture().Create<string []>())

​