  for i, tt := range tests {   b, tmpPath := backend.NewDefaultTmpBackend()   s := NewStore(b, &lease.FakeLessor{}, nil)    s.Put([]byte("foo"), []byte("bar"), lease.NoLease)   s.Put([]byte("foo0"), []byte("bar0"), lease.NoLease)   s.Put([]byte("foo0"), []byte("bar0"), lease.NoLease)   