type UnitQuantity = private UnitQuantity of int
// ^ private constructor

// define a module with the same name as the type
module UnitQuantity =
    /// Define a "smart constructor" for UnitQuantity
    /// int -> Result<UnitQuantity,string>
    let create qty =
        if qty < 1 then
            // failure
            Error "UnitQuantity can not be negative"
        else if qty > 1000 then
            // failure
            Error "UnitQuantity can not be more than 1000"
        else
            // success -- construct the return value
            Ok (UnitQuantity qty)

let ``Check UnitQuantity.create is one`` () =

    // ARRANGE
    let expected = 1

    // ACT
    //let unitQtyResult = UnitQuantity.create 1
    match UnitQuantity.create 1 with
    | Error msg -> 0
        //printfn "Failure, Message is %s" msg
    | Ok x -> 0
       // let innerValue = UnitQuantity.value actual

    // ASSERT
    //Assert.Equal(expected,actual)