Given below was my c# code :

        public async Task<bool>? CallValidationLayer(string id) {
            try
            {

                var bodyContent = JsonConvert.SerializeObject(new { id = id });
                var content = new StringContent(bodyContent, Encoding.UTF8, "application/json");
                HttpResponseMessage validationResult = await _HttpClient.PostAsync(_ValidationLayerAPI, content);
                if (validationResult.IsSuccessStatusCode)
                {
                    return true;
                }

                return false;

            }
            catch(Exception ex)
            {
                return false;
            }
        }

For the above code i have write a test :

        [Fact]
        public async Task CallValidationLayerTrue()
        {
            //Arrange
            string id = "test";
            mockMessageHandler.Protected()
                .Setup<Task<HttpResponseMessage>>("SendAsync", ItExpr.IsAny<HttpRequestMessage>(), ItExpr.IsAny<CancellationToken>())
                .ReturnsAsync(
                  new HttpResponseMessage
                  {
                      StatusCode = HttpStatusCode.OK
                  });

            //Act
            var result = await _mapper.CallValidationLayer(id);

            //Assert 
            Assert.True(result);
        }

for the above testing the “validationResult” was always null why

i am expecting response status code from “validationResult”