Added benchmarks for finding trending projects

spec/benchmarks/finders/trending_projects_finder_spec.rb

+require 'spec_helper'
+
+describe TrendingProjectsFinder, benchmark: true do
+  describe '#execute' do
+    let(:finder) { described_class.new }
+    let(:user)   { create(:user) }
+
+    # to_a is used to force actually running the query (instead of just building
+    # it).
+    benchmark_subject { finder.execute(user).non_archived.to_a }
+
+    it { is_expected.to iterate_per_second(500) }
+  end
+end

spec/benchmarks/models/project_spec.rb

+require 'spec_helper'
+
+describe Project, benchmark: true do
+  describe '.trending' do
+    let(:group)    { create(:group) }
+    let(:project1) { create(:empty_project, :public, group: group) }
+    let(:project2) { create(:empty_project, :public, group: group) }
+
+    let(:iterations) { 500 }
+
+    before do
+      2.times do
+        create(:note_on_commit, project: project1)
+      end
+
+      create(:note_on_commit, project: project2)
+    end
+
+    describe 'without an explicit start date' do
+      benchmark_subject { described_class.trending.to_a }
+
+      it { is_expected.to iterate_per_second(iterations) }
+    end
+
+    describe 'with an explicit start date' do
+      let(:date) { 1.month.ago }
+
+      benchmark_subject { described_class.trending(date).to_a }
+
+      it { is_expected.to iterate_per_second(iterations) }
+    end
+  end
+end