When developing an application using TDD or BDD you would write the
tests/specs first. So the matchers that remarkable provides would
allow you to describe the expected behavior of your application and
when all the tests/specs pass your application should work correctly.
However, testing and how in-depth you test is optional, if you work by
yourself or your company does not require test coverage and you find
it cumbersome then don't. But, without test coverage if by chance that
one line disappears your application could begin to act in unexpected
ways and hunting down that problem would be a waste of time. Testing
is insurance against regression that happens from time to time while
an application is being developed and maintained.
Louis T.
@negonicrac