Add init test for ProjectSearchResults

See: https://github.com/gitlabhq/gitlabhq/pull/9368#issuecomment-110350335

spec/lib/gitlab/project_search_results_spec.rb

+require 'spec_helper'
+
+describe Gitlab::ProjectSearchResults do
+  let(:project) { create(:project) }
+  let(:query) { 'hello world' }
+
+  describe 'initialize with empty ref' do
+    let(:results) { Gitlab::ProjectSearchResults.new(project.id, query, '') }
+
+    it { expect(results.project).to eq(project) }
+    it { expect(results.repository_ref).to be_nil }
+    it { expect(results.query).to eq('hello\\ world') }
+  end
+
+  describe 'initialize with ref' do
+    let(:ref) { 'refs/heads/test' }
+    let(:results) { Gitlab::ProjectSearchResults.new(project.id, query, ref) }
+
+    it { expect(results.project).to eq(project) }
+    it { expect(results.repository_ref).to eq(ref) }
+    it { expect(results.query).to eq('hello\\ world') }
+  end
+end