public void TestSignRequest()
        {
            var request       = TestData.ApiRequest;
            var signedRequest = signer.SignRequest(request, TestData.RequestNonce);

            Assert.That(signedRequest.UserId, Is.EqualTo(request.UserId));
            Assert.That(signedRequest.Header, Is.EqualTo(request.Header));
            Assert.That(signedRequest.Body, Is.EqualTo(request.Body));
            Assert.That(signedRequest.Nonce, Is.EqualTo(TestData.RequestNonce));
            AssertSignatureIsValide(request, signedRequest);
        }