You're right! And I absolutely agree. The problem is that I'll be working in different setups and I think that the most portable method is regex. It can just be copied into any test and it will also allow for capturing and detection of certain parts of posts that are supposed to be account names.
A longer test such as Steemit's would be ideal for many things and I think that you're right about it being more robust and solid, but it's at the same time more complicated and time-consuming.