func splitTestRange(store *storage.Store, key, splitKey proto.Key, t *testing.T) *storage.Range {
	rng := store.LookupRange(key, key)
	if rng == nil {
		t.Fatalf("couldn't lookup range for key %q", key)
	}
	desc, err := store.NewRangeDescriptor(splitKey, rng.Desc().EndKey, rng.Desc().Replicas)
	if err != nil {
		t.Fatal(err)
	}
	newRng, err := storage.NewRange(desc, store)
	if err != nil {
		t.Fatal(err)
	}
	if err := store.SplitRange(rng, newRng); err != nil {
		t.Fatal(err)
	}
	return newRng
}