module IsbnVerifierTests open FsUnit.Xunit open Xunit open IsbnVerifier [] let ``Valid isbn`` () = isValid "3-598-21508-8" |> should equal true [] let ``Invalid isbn check digit`` () = isValid "3-598-21508-9" |> should equal false [] let ``Valid isbn with a check digit of 10`` () = isValid "3-598-21507-X" |> should equal true [] let ``Check digit is a character other than X`` () = isValid "3-598-21507-A" |> should equal false [] let ``Invalid check digit in isbn is not treated as zero`` () = isValid "4-598-21507-B" |> should equal false [] let ``Invalid character in isbn is not treated as zero`` () = isValid "3-598-P1581-X" |> should equal false [] let ``X is only valid as a check digit`` () = isValid "3-598-2X507-9" |> should equal false [] let ``Only one check digit is allowed`` () = isValid "3-598-21508-96" |> should equal false [] let ``X is not substituted by the value 10`` () = isValid "3-598-2X507-5" |> should equal false [] let ``Valid isbn without separating dashes`` () = isValid "3598215088" |> should equal true [] let ``Isbn without separating dashes and X as check digit`` () = isValid "359821507X" |> should equal true [] let ``Isbn without check digit and dashes`` () = isValid "359821507" |> should equal false [] let ``Too long isbn and no dashes`` () = isValid "3598215078X" |> should equal false [] let ``Too short isbn`` () = isValid "00" |> should equal false [] let ``Isbn without check digit`` () = isValid "3-598-21507" |> should equal false [] let ``Check digit of X should not be used for 0`` () = isValid "3-598-21515-X" |> should equal false [] let ``Empty isbn`` () = isValid "" |> should equal false [] let ``Input is 9 characters`` () = isValid "134456729" |> should equal false [] let ``Invalid characters are not ignored after checking length`` () = isValid "3132P34035" |> should equal false [] let ``Invalid characters are not ignored before checking length`` () = isValid "3598P215088" |> should equal false [] let ``Input is too long but contains a valid isbn`` () = isValid "98245726788" |> should equal false