G+ response to some F# code

LotParser.fs

open System.Text.RegularExpressions
open FsUnit
open NUnit.Framework

let parseLot lot = 
    match lot with
    | x when Regex.Match(x, @"^\d+$").Success -> [ x |> int ]
    | x when Regex.Match(x, @"^\d+-\d+$").Success -> 
        let parts = x.Split('-')
        [ parts.[0] |> int..parts.[1] |> int ]
    | _ -> []

let splitLots (lots : string) = 
    lots.Replace(" ", "").Split(',') 
    |> Array.toList
    |> List.fold (fun acc l -> acc @ (parseLot l)) []

[<Test>]
let ``Given string of digits, splitLots2 should return list of digits``() = 
    splitLots "1" |> should equal [ 1 ]
    splitLots "1, 2, 3, 5, 7, 10" |> should equal [ 1; 2; 3; 5; 7; 10 ]

[<Test>]
let ``Given string range of digits, splitLots2 should return list of digits``() = 
    splitLots "1-3" |> should equal [ 1; 2; 3 ]

[<Test>]
let ``Given string with digits and range, splitLots2 should return a list of digits``() = 
    splitLots "1, 2, 5-7, 10-12, 15" 
    |> should equal [ 1; 2; 5; 6; 7; 10; 11; 12; 15 ]