Remove factories from projects cleanup spec

spec/migrations/cleanup_nonexisting_namespace_pending_delete_projects_spec.rb

 require 'spec_helper'
 require Rails.root.join('db', 'post_migrate', '20170816102555_cleanup_nonexisting_namespace_pending_delete_projects.rb')
-describe CleanupNonexistingNamespacePendingDeleteProjects do
-  before do
-    # Stub after_save callbacks that will fail when Project has invalid namespace
-    allow_any_instance_of(Project).to receive(:ensure_storage_path_exist).and_return(nil)
-    allow_any_instance_of(Project).to receive(:update_project_statistics).and_return(nil)
-  end
+describe CleanupNonexistingNamespacePendingDeleteProjects, :migration do
+  let(:projects) { table(:projects) }
+  let(:namespaces) { table(:namespaces) }
   describe '#up' do
-    set(:some_project) { create(:project) } # rubocop:disable RSpec/FactoriesInMigrationSpecs
+    let!(:some_project) { projects.create! }
+    let(:namespace) { namespaces.create!(name: 'test', path: 'test') }
     it 'only cleans up when namespace does not exist' do
-      create(:project, pending_delete: true) # rubocop:disable RSpec/FactoriesInMigrationSpecs
-      project = build(:project, pending_delete: true, namespace: nil, namespace_id: Namespace.maximum(:id).to_i.succ) # rubocop:disable RSpec/FactoriesInMigrationSpecs
-      project.save(validate: false)
+      projects.create!(pending_delete: true, namespace_id: namespace.id)
+      project = projects.create!(pending_delete: true, namespace_id: 0)
       expect(NamespacelessProjectDestroyWorker).to receive(:bulk_perform_async).with([[project.id]])
@@ -22,7 +19,7 @@ describe CleanupNonexistingNamespacePendingDeleteProjects do
     end
     it 'does nothing when no pending delete projects without namespace found' do
-      create(:project, pending_delete: true, namespace: create(:namespace)) # rubocop:disable RSpec/FactoriesInMigrationSpecs
+      projects.create!(pending_delete: true, namespace_id: namespace.id)
       expect(NamespacelessProjectDestroyWorker).not_to receive(:bulk_perform_async)