Add spec for labels auto complete

ee/spec/services/groups/autocomplete_service_spec.rb

+require 'spec_helper'
+
+describe Groups::AutocompleteService do
+  let!(:group) { create(:group, :nested, avatar: fixture_file_upload('spec/fixtures/dk.png')) }
+  let!(:sub_group) { create(:group, parent: group) }
+  let(:user) { create(:user) }
+  let(:epic) { create(:epic, group: group, author: user) }
+
+  before do
+    create(:group_member, group: group, user: user)
+  end
+
+  def user_to_autocompletable(user)
+    {
+      username: user.username,
+      name: user.name,
+      avatar_url: user.avatar_url
+    }
+  end
+
+  describe '#labels' do
+    let!(:label1) { create(:group_label, group: group) }
+    let!(:label2) { create(:group_label, group: group) }
+    let!(:sub_group_label) { create(:group_label, group: sub_group) }
+    let!(:parent_group_label) { create(:group_label, group: group.parent) }
+
+    it 'returns labels from own group and ancestor groups' do
+      service = described_class.new(group, user)
+      result = service.labels
+
+      expected_labels = [label1, label2, parent_group_label]
+
+      expect(result.size).to eq(3)
+      expect(result.map(&:title)).to contain_exactly(*expected_labels.map(&:title))
+    end
+
+    context 'some labels are already assigned' do
+      before do
+        epic.labels << label1
+      end
+
+      it 'marks already assigned as set' do
+        service = described_class.new(group, user)
+        result = service.labels(epic)
+
+        expected_labels = [label1, label2, parent_group_label]
+
+        expect(result.size).to eq(3)
+        expect(result.map { |label| label['title'] }).to contain_exactly(*expected_labels.map(&:title))
+
+        epic.labels.each do |assigned_label|
+
+          expect(result.find { |label| label['title'] == assigned_label.title }[:set]).to eq(true)
+        end
+      end
+    end
+  end
+end