BasicChecks.fs

module BasicChecks

open Xunit
open FsCheck
open FsCheck.Xunit

type Positive =
    static member Int() =
        Arb.Default.Int32()
        |> Arb.mapFilter abs (fun t -> t > 0)

type PositiveFloat =
    static member Float() =
        Arb.Default.Float()
        |> Arb.mapFilter abs (fun t -> t > 0.0)

type SvgProperty() =
    inherit PropertyAttribute(Arbitrary = [| typeof<PositiveFloat> |])


let isTagEnclosed (tag:string) =
    let trimmedTag = tag.Trim()
    trimmedTag.[0..0] = "<" && trimmedTag.[(trimmedTag.Length - 2)..(trimmedTag.Length - 1)] = "/>"

let happensEvenly chr (str:string) =
    str.ToCharArray()
    |> Array.fold (fun acc c -> if chr = c then acc + 1 else acc) 0
    |> (fun x -> x % 2 = 0)

let isDepthNoMoreThanOne left right (str:string) =
    str.ToCharArray()
    |> Array.scan
        (fun acc c ->
            match c with
                | c when c = left -> acc + 1
                | c when c = right -> acc - 1
                | _ -> acc
        ) 0
    |> Array.max
    |> (>=) 1

let isMatched left right (str:string) =
    str.ToCharArray()
    |> Array.fold

        (fun acc c ->
            match c with
                | c when c = left -> acc + 1
                | c when c = right -> acc - 1
                | _ -> acc
        ) 0 = 0

let checkBodylessTag name tag =
    Assert.True(isMatched '<' '>' tag)
    Assert.True(isDepthNoMoreThanOne '<' '>' tag)
    Assert.True(happensEvenly '"' tag)
    Assert.True(happensEvenly ''' tag)
    Assert.True(isTagEnclosed tag)

let checkTag name tag =
    Assert.True(isMatched '<' '>' tag)
    Assert.True(isDepthNoMoreThanOne '<' '>' tag)
    Assert.True(happensEvenly '"' tag)
    Assert.True(happensEvenly ''' tag)