This adds a test to the recent GetLayerName function, and moves
it to the base.h file for re-use for any code that needs a
layer name.
This test covers the case that caused lp:1824750 [1].
[1]: https://bugs.launchpad.net/kicad/+bug/1824750
The SEXPR class is a useful general-purpose S-Expression library
class and can (maybe) be used else where. It also should get
test coverage, as even if noone else uses it, it's critical for the
kicad2step exporter.
Also add some test coverage for some kicad2step routines. For now,
they're not useful outside kicad2step, but they are at least a useful
reference for S-Expression parsing.
The addition of very small segments in OCE triggers sliver
removal/cleanup in the BREP generation that can get stuck in a very long
loop during STEP export of boards. These were introduced to ensure
closure of boards with small gaps that were too big for OCE to consider
joined.
Removing the small segments allows STEP export to proceed in a
reasonable time. This also decreases the default minimum gap size that
kicad2step uses to determine curve matching. This prevents mis-matching
small curves
Fixes: lp:1784626
* https://bugs.launchpad.net/kicad/+bug/1784626