existing = create(:relation_tag)
tag = build(:relation_tag, :relation => existing.relation, :k => existing.k, :v => existing.v)
assert_predicate tag, :new_record?
existing = create(:relation_tag)
tag = build(:relation_tag, :relation => existing.relation, :k => existing.k, :v => existing.v)
assert_predicate tag, :new_record?