public async void LastPriceAsync_should_success(string jsonString, string currencyPair)
        {
            //arrange
            var response = TestHelper.CreateJsonResponse(jsonString);

            var obj = new PublicApi(TestHelper.CreateApiClientWithMockHttpAccessor(response));

            //act
            var actual = await obj.LastPriceAsync(currencyPair);

            //assert
            Assert.NotNull(actual);
            Assert.IsAssignableFrom <LastPriceResponse>(actual);
        }