public void CanGenerateHashForMessage()
{
// ARRANGE
var hashRequest = Substitute.For <HashRequest>();
var expectedHashRespone = Substitute.For <HashResponse>();
_cryptographer.GenerateHash(hashRequest).Returns(expectedHashRespone);
// ACT
var result = _subjectUnderTest.Post(hashRequest);
// ASSERT
Assert.That(result, Is.Not.Null);
_cryptographer.Received(1).GenerateHash(hashRequest);
}