With the new Rails 5 behavior, `belong_to` will check to ensure that the
association has a presence validation on it. In some cases, however,
this is not desirable. For instance, say we have this setup:
class Employee < ApplicationRecord
# Assume belongs_to_required_by_default is true
belongs_to :manager
before_validation :add_manager
private
def add_manager
self.manager = Manager.create
end
end
In this case, even though the association is effectively defined with
`required: true`, the ensuing presence validation never fails, because
`manager` is always set to something before validations kick off. So
this test won't work:
it { should belong_to(:manager) }
To get around this, this commit allows us to say:
it { should belong_to(:manager).without_presence_validation }
which instructs the matcher not to test for any presence (or absence,
for that matter) of a presence validation, mimicking the pre-Rails 5
behavior.
707d87dbd6