require 'spec_helper' describe Gitlab::SQL::Union, lib: true do let(:relation_1) { User.where(email: 'alice@example.com').select(:id) } let(:relation_2) { User.where(email: 'bob@example.com').select(:id) } def to_sql(relation) relation.reorder(nil).to_sql end describe '#to_sql' do it 'returns a String joining relations together using a UNION' do union = described_class.new([relation_1, relation_2]) expect(union.to_sql).to eq("#{to_sql(relation_1)}\nUNION\n#{to_sql(relation_2)}") end it 'skips Model.none segements' do empty_relation = User.none union = described_class.new([empty_relation, relation_1, relation_2]) expect{User.where("users.id IN (#{union.to_sql})").to_a}.not_to raise_error expect(union.to_sql).to eq("#{to_sql(relation_1)}\nUNION\n#{to_sql(relation_2)}") end end end