public async Task ReturnWithOutWhat()
        {
            var myDoUntilClass = new DoUntilClass();

            var convertedUsedUntil = JsonConvert.SerializeObject(usedUntil);
            var data = new StringContent(convertedUsedUntil.ToString(),
                                         encoding: Encoding.UTF8,
                                         mediaType: "application/json");

            var response = await Client.PostAsync("dountil", data);

            var responseString = await response.Content.ReadAsStringAsync();

            Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
        }
        public IActionResult DoUntil([FromBody] DoUntilClass myDoUntilClass, string what)
        {
            if (what == "factor")
            {
                return(Json(new { result = myDoUntilClass.Factor() }));
            }

            if (what == "sum")
            {
                return(Json(new { result = myDoUntilClass.Sum() }));
            }

            if (string.IsNullOrEmpty(what))
            {
                return(NotFound());
            }

            if (myDoUntilClass == null)
            {
                return(Json(new { error = "Please provide a number!" }));
            }

            if (myDoUntilClass.Until == null)
            {
                return(Json(new { error = "Please provide a number!" }));
            }

            if (string.IsNullOrEmpty(what))
            {
                return(Json(new { error = "Please provide a number!" }));
            }

            if (what == null)
            {
                return(Json(new { error = "Please provide a number!" }));
            }

            else
            {
                return(Json(new { error = "Please provide a number!" }));
            }
        }