without that check, in theory our test runner will tolerate
a non-zero return value, like throwing or failing an assert,
which is not what we want....
guess these happenend to get in by forgetting to
add this check when switching a test from PLANNED to TEST
this was a classical example of a muddled and messed-up design,
driven just by the fact that I wanted to "spare" some functions,
with the net effect of writing more functions, plus a proxy class
plus create a lot of confusion for the reader.
This was easy to resolve though, once I resorted to the
general adivice to make public interface methods final,
make the extension ponts protected and never
to chain two extension points
due to the new automatic string conversion in operator<<
the representation of objects has changed occasionally.
I've investigated and verified all those incidents.
Initially I've deliberately omitted those, to nudge towards
using time quantisation and TCode formatting for any external
representation of time values.
While this recommendation is still valid, the overloaded
string conversion turns out to be helpful for unit testing
and diagnostics in compound data structures.
See Record<GenNode>
the buildsystem will now pick up and link
all test cases according to the layer, e.g.
backend tests will automatically be linked
against the backend + library solely.
In the course of the preceeding work, I changed the
standard Time formatting in time.c, such as to omit
the leading "0" on the hour; it doesn't seem likely
that displayed hour values will frequently have
two digits...
