1 files changed, 16 insertions, 6 deletions
diff --git a/spec/lib/gitlab/sql/union_spec.rb b/spec/lib/gitlab/sql/union_spec.rb
index 0cdbab87544..849edb09476 100644
--- a/spec/lib/gitlab/sql/union_spec.rb
+++ b/spec/lib/gitlab/sql/union_spec.rb
@@ -1,16 +1,26 @@
 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
-      rel1  = User.where(email: 'alice@example.com')
-      rel2  = User.where(email: 'bob@example.com')
-      union = described_class.new([rel1, rel2])
+      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
 
-      sql1 = rel1.reorder(nil).to_sql
-      sql2 = rel2.reorder(nil).to_sql
+    it 'skips Model.none segements' do
+      empty_relation = User.none
+      union = described_class.new([empty_relation, relation_1, relation_2])
 
-      expect(union.to_sql).to eq("#{sql1}\nUNION\n#{sql2}")
+      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