Fix a transient failure in the `Explore::ProjectsController` spec

spec/controllers/explore/projects_controller_spec.rb

 require 'spec_helper'
 
 describe Explore::ProjectsController do
-  let(:user) { create(:user) }
-  let(:visibility) { :public }
-
   describe 'GET #trending' do
-    let!(:project_1) { create(:project, visibility, ci_id: 1) }
-    let!(:project_2) { create(:project, visibility, ci_id: 2) }
-
-    let!(:trending_project_1) { create(:trending_project, project: project_1) }
-    let!(:trending_project_2) { create(:trending_project, project: project_2) }
+    context 'sorting by update date' do
+      let(:project1) { create(:empty_project, :public, updated_at: 3.days.ago) }
+      let(:project2) { create(:empty_project, :public, updated_at: 1.day.ago) }
 
-    before do
-      sign_in(user)
-    end
+      before do
+        create(:trending_project, project: project1)
+        create(:trending_project, project: project2)
+      end
 
-    context 'sorting by update date' do
       it 'sorts by last updated' do
         get :trending, sort: 'updated_desc'
-        expect(assigns(:projects)).to eq [project_2, project_1]
+
+        expect(assigns(:projects)).to eq [project2, project1]
       end
 
       it 'sorts by oldest updated' do
         get :trending, sort: 'updated_asc'
-        expect(assigns(:projects)).to eq [project_1, project_2]
+
+        expect(assigns(:projects)).to eq [project1, project2]
       end
     end
   end