d6fc1d6a33 test: add coverage for dust mempool policy (`-dustrelayfee` setting) (Sebastian Falbesoner)
8a5dbe2879 test: add `CScript` method for checking for witness program (Sebastian Falbesoner)
Pull request description:
This PR adds missing test coverage for the `-dustrelayfee` setting, which specifies the fee-rate used to define dust. Output scripts for all common types that are treated as standard by default (P2PK, P2(W)PKH, P2(W)SH, P2TR, bare multisig, null data, unknown witness versions v2+) are created and then checked for dust-mempool-policy each via the `testmempoolaccept` RPC: a tx with an output's nValue equal to the dust threshold should be accepted, one with an nValue of just one 1 satoshi below that should be rejected with reason `dust`. This is repeatedly done for a fixed (but obviously somewhat arbitrary) list of different `-dustrelayfee` settings on a single node, including the default and zero (i.e. no dust limit) settings.
Note that the first commit introduces a necessary `CScript` helper method `IsWitnessProgram` (using PascalCase in Python is likely controversial; in this case the style for the already existing method `GetSigOpCount` was followed, which also refers to a method in the core `CScript` class).
Some historical information about dust, contributed by pablomartin4btc:
"The concept of dust was first introduced in https://github.com/bitcoin/bitcoin/pull/2577. This [commit](eb30d1a5b2) from https://github.com/bitcoin/bitcoin/pull/9380 introduced the -dustrelayfee option. Previous to that PR, the dust feerate was whatever -minrelaytxfee was set to."
ACKs for top commit:
LarryRuane:
ACK d6fc1d6a33
glozow:
ACK d6fc1d6a33
kouloumos:
ACK d6fc1d6a33
Tree-SHA512: 35ea2b2497dfb466395af5665bb217f7250aa7cab9dc43539a5658ab69a454e3623ff58fce7489fcc1105b37f8cb4840a93cec658c5df1de611732bc6439ccad
2182149dc5