tests: specific tests for modulo results == 0

two extra sanity checks in the unit test

Signed-off-by: Matthias Kretz <kretz@kde.org>
gather test: converted to new subscript syntax

I also converted it to the new test definition format.

Signed-off-by: Matthias Kretz <kretz@kde.org>
gather test: converted to new subscript syntax

I also converted it to the new test definition format.

Signed-off-by: Matthias Kretz <kretz@kde.org>