Send another UTXO if this is a neutrino backend. When sweeping anchors,
there are two transactions created, `local_sweep_tx` for sweeping
Alice's anchor on the local commitment, `remote_sweep_tx` for sweeping
her anchor on the remote commitment. Whenever the force close
transaction is published, Alice will always create these two
transactions to sweep her anchor.
On the other hand, when creating the sweep txes, the anchor itself is
not able to cover the fee, so another wallet UTXO is needed. In our
test case, there's a change output that can be used from the above
funding process. And it's used by both sweep txes - when `lnd` happens
to create the `remote_sweep_tx` first, it will receive an error since
its parent tx, the remote commitment, is not known, hence freeing the
change output to be used by `local_sweep_tx`. For neutrino client,
however, it will consider the transaction which sweeps the remote anchor
as an orphan tx, and it will neither send it to the mempool nor return
an error to free the change output. Thus, if the change output is
already used in `remote_sweep_tx`, we won't have UTXO to create
`local_sweep_tx`.
This commit adds the missing check for anchor sweep in test
`revoked_uncooperative_close_retribution_altruist_watchtower`, also
change the mempool check a bit so it's easier to track.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
This commit removes the context as a param needed when calling methods
of HarnessNode. This change moves the context management inside
HarnessNode, aside from saving us a few lines, it makes the context
creation/timeout less error-prone.
In this commit, we put the context initialization inside
openChannelAndAssert, thus saving us a few lines and making sure the
context is always properly handled.
