Test whether factory objects can be created at a same time and coexist
We currently test whether factories are valid in spec/factories_spec.rb in isolation (we have a separate example for each factory, thus we have an empty database when we build it). That means that we do not test if fabricated objects can coexist with each other / be created at the same time.
Currently some fabricated objects can not be created at the same time without overriding attributes - mostly because of unique fields in database. This may lead to bugs in specs that are difficult to find, because it may not be possible to fabricate two objects out-of-the box.
Should we change that?