Added basic unit tests, helps with debugging

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added a strategy for partially empty arrays and for integer-only ones

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Update core-lib, fixes verification of a benchmark

Signed-off-by: Stefan Marr <git@stefan-marr.de>