Repository: bitcoin/bitcoin
File: test/functional/feature_assumevalid.py (Python)

Code before:
We build a chain that includes and invalid signature for one of the
transactions:

    0:        genesis block
    1:        block 1 with coinbase transaction output.
    2-101:    bury that block with 100 blocks so the coinbase transaction
              output can be spent
    102:      a block containing a transaction spending the coinbase
              transaction output. The transaction has an invalid signature.
    103-2202: bury the bad block with just over two weeks' worth of blocks
              (2100 blocks)

Start three nodes:

    - node0 has no -assumevalid parameter. Try to sync to block 2202. It will
      reject block 102 and only sync as far as block 101
    - node1 has -assumevalid set to the hash of block 102. Try to sync to
      block 2202. node1 will sync all the way to block 2202.
    - node2 has -assumevalid set to the hash of block 102. Try to sync to
      block 200. node2 will reject block 102 since it's assumed valid, but it
      isn't buried by at least two weeks' work.
"""

from test_framework.blocktools import (
    COINBASE_MATURITY,
    create_block,
    create_coinbase,
)
from test_framework.messages import (
    CBlockHeader,
    COutPoint,
    CTransaction,
    CTxIn,
    CTxOut,
    msg_block,
    msg_headers,
)
from test_framework.p2p import P2PInterface
from test_framework.script import (
    CScript,
    OP_TRUE,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import assert_equal
from test_framework.wallet_util import generate_keypair


class BaseNode(P2PInterface):
    def send_header_for_blocks(self, new_blocks):
        headers_message = msg_headers()
        headers_message.headers = [CBlockHeader(b) for b in new_blocks]

Review comment (suggestion):
nit:
```suggestion
    - node5 starts with no -assumevalid parameter. Reindex to deterministically hit
      "assumevalid hash not in headers" and "below minimum chainwork".
```

Code after:
We build a chain that includes an invalid signature for one of the transactions:

    0:        genesis block
    1:        block 1 with coinbase transaction output.
    2-101:    bury that block with 100 blocks so the coinbase transaction
              output can be spent
    102:      a block containing a transaction spending the coinbase
              transaction output. The transaction has an invalid signature.
    103-2202: bury the bad block with just over two weeks' worth of blocks
              (2100 blocks)

Start a few nodes:

    - node0 has no -assumevalid parameter. Try to sync to block 2202. It will
      reject block 102 and only sync as far as block 101
    - node1 has -assumevalid set to the hash of block 102. Try to sync to
      block 2202. node1 will sync all the way to block 2202.
    - node2 has -assumevalid set to the hash of block 102. Try to sync to
      block 200. node2 will reject block 102 since it's assumed valid, but it
      isn't buried by at least two weeks' work.
    - node3 has -assumevalid set to the hash of block 102. Feed a longer
      competing headers-only branch so block #1 is not on the best header chain.
    - node4 has -assumevalid set to the hash of block 102. Submit an alternative
      block #1 that is not part of the assumevalid chain.
    - node5 starts with no -assumevalid parameter. Reindex to hit
      "assumevalid hash not in headers" and "below minimum chainwork".
"""

from test_framework.blocktools import (
    COINBASE_MATURITY,
    create_block,
    create_coinbase,
)
from test_framework.messages import (
    CBlockHeader,
    COutPoint,
    CTransaction,
    CTxIn,
    CTxOut,
    msg_block,
    msg_headers,
)
from test_framework.p2p import P2PInterface
from test_framework.script import (
    CScript,
    OP_TRUE,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import assert_equal
from test_framework.wallet_util import generate_keypair