39d135e79f test: MiniWallet: respect fee_rate for target_weight, use in mempool_limit.py (Sebastian Falbesoner)
b2f0a9f8b0 test: add framework functional test for MiniWallet's tx padding (Sebastian Falbesoner)
c17550bc3a test: MiniWallet: fix tx padding (`target_weight`) for large sizes, improve accuracy (Sebastian Falbesoner)
Pull request description:
MiniWallet allows to create padded transactions that are equal or slightly above a certain `target_weight` (first introduced in PR #25379, commit 1d6b438ef0), which can be useful especially for mempool-related tests, e.g. for policy limit checks or scenarios to trigger mempool eviction. Currently the `target_weight` parameter doesn't play together with `fee_rate` though, as the fee calculation is incorrectly based on the tx vsize before the padding output is added, so the fee-rate is consequently far off. This means users are forced to pass an absolute fee, which can be quite inconvenient and leads to lots of duplicated "calculate absolute fee from fee-rate and vsize" code with the pattern `fee = (feerate / 1000) * (weight // 4)` on the call-sites.
This PR first improves the tx padding itself to be more accurate, adds a functional test for it, and fixes the `fee_rate` treatment for the `{create,send}_self_transfer` methods. (Next step would be to enable this also for the `_self_transfer_multi` methods, but those currently don't even offer a `fee_rate` parameter). Finally, the ability to pass both `target_weight` and `fee_rate` is used in the `mempool_limit.py` functional test. There might be more use-cases in other tests, that could be done in a follow-up.
ACKs for top commit:
rkrux:
tACK [39d135e](39d135e79f)
ismaelsadeeq:
Code Review ACK 39d135e79f🚀
glozow:
light review ACK 39d135e79f
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e6e4c18a9b