NaturalSpecとunquoteを併用したら出力がリッチにならないかな、と思ったなれの果て

UnquoteNaturalSpec.fs

// NaturalSpec: https://github.com/forki/NaturalSpec
// unquote: http://code.google.com/p/unquote/

open NaturalSpec.Utils
open NaturalSpec
open NUnit.Framework
open Swensen.Unquote

let check (assertType,a,b,value) =
  let outputFail f message =
    let s =
        f
        |> reduceFully
        |> List.map decompile
        |> List.fold (fun s x -> s + sprintf "%s\r\n" x) message
    s |> toSpec
    s |> Assert.Fail
  let evalA = eval a
  let evalB = eval b
  match assertType with
  | Equality -> if evalA <> evalB then outputFail <@ %b = %a @> "\r\nElements are not equal.\r\n"
  | Inequality -> if evalA = evalB then outputFail <@ %b <> %a @> "\r\nElements should not be equal.\r\n"
  | IsTrue -> test <@ %b = %a @>
  | IsFalse -> test <@ %b <> %a @>
  value

let should f x y =
  toSpec "should "
  f <@ x @> y |> check

let shouldn't f x y =
  toSpec "sholdn't "
  f <@ x @> y |> not' |> check

let have (f:Quotations.Expr<'a -> bool>) value =
  toSpec "have "
  IsTrue,<@ true @>,<@ value |> %f @>,value

let removing x seq = <@ Seq.filter ((<>) x) seq @>

let length n seq =
  printMethod n
  let l = seq |> eval |> Seq.length
  if n <> l then
    <@ %seq |> Seq.length = n @>
    |> reduceFully
    |> List.map decompile
    |> List.fold (fun s x -> s + sprintf "%s\r\n" x) ""
    |> Assert.Fail
  true

let contain x (seq:Quotations.Expr<'a seq>) =
  let x = eval x
  printMethod x
  IsTrue,<@ true @>,<@ Seq.exists ((=) x) %seq @>,seq

let duplicates (seq:Quotations.Expr<'a seq>) =
  printMethod ""
  let dict = new System.Collections.Generic.HashSet<'a>()
  seq |> eval |> Seq.fold (fun d i -> d || (not (dict.Add i))) false

[<Scenario>]
let ``divide test``() =
  Given (1,1)
  ||> When (fun x y -> <@ x / y @>)
  |> It should equal 2
  |> Verify

[<Scenario>]
let ``list test``() =
  Given [1;2;3;4;5]
  |> When removing 3
  |> It shouldn't contain 3
  |> It should contain 4
  |> It should have (length 4)
  |> It shouldn't have duplicates
  |> Verify