# task-050

Every time a bucket's `balance` or `balance_cache_key` properties are set or
updated, it must be the case that running `calculate_bucket_balance(bucket)`
under the pretence that `is_bucket_balance_up_to_date(bucket)` returns FALSE
would leave the bucket's `balance` and `balance_cache_key` unchanged.

Source: req-071

Epic: epic-008