public void Register_SimpleType_ShouldRegisterAsAMessage()
{
// Arrange
MessageRegistry messageRegistry = new MessageRegistry();
// Act
messageRegistry.Register(typeof(FakeCommand));
messageRegistry.Register(typeof(FakeCommand));
messageRegistry.Register(typeof(int));
// Assert
messageRegistry.Should().HaveCount(1);
messageRegistry.Single().MessageType.Should().Be(typeof(FakeCommand));
}