Tune the spec to test the bare minimum

Instead of running the sync 10 times, just run it twice and see if the
worker attempts other projects than it did in the first run.

spec/workers/geo/repository_sync_worker_spec.rb

@@ -93,25 +93,21 @@ describe Geo::RepositorySyncWorker do
 
     context 'all repositories fail' do
       before do
-        allow_any_instance_of(described_class).to receive(:db_retrieve_batch_size).and_return(4)
-        allow_any_instance_of(described_class).to receive(:max_capacity).and_return(5)
+        allow_any_instance_of(described_class).to receive(:db_retrieve_batch_size).and_return(2) # Must be >1 because of the Geo::BaseSchedulerWorker#interleave
+        allow_any_instance_of(described_class).to receive(:max_capacity).and_return(3) # Must be more than db_retrieve_batch_size
         allow_any_instance_of(Project).to receive(:ensure_repository).and_raise(Gitlab::Shell::Error.new('foo'))
         allow_any_instance_of(Geo::ProjectSyncWorker).to receive(:sync_wiki?).and_return(false)
         allow_any_instance_of(Geo::RepositorySyncService).to receive(:expire_repository_caches)
-        allow_any_instance_of(Geo::RepositorySyncService).to receive(:try_obtain_lease) { |&arg| arg.call }
 
-        create_list(:project, 20, :random_last_repository_updated_at)
+        create_list(:project, 4, :random_last_repository_updated_at)
       end
 
-      it 'attempts to sync them all' do
-        Sidekiq::Testing.inline! do
-          10.times do
-            subject.perform
-            break if Geo::ProjectRegistry.count == Project.count
-          end
-        end
+      it 'does not retry the same projects over and over again' do
+        Sidekiq::Testing.inline! { subject.perform }
 
-        expect(Geo::ProjectRegistry.count).to eq(Project.count)
+        expect do
+          Sidekiq::Testing.inline! { subject.perform }
+        end.to change { Geo::ProjectRegistry.count }
       end
     end
   end