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

Code before:
            assert_equal(self.nodes[0].gettransaction(bump2)["confirmations"], 1)
            assert_equal(tx2 in self.nodes[1].getrawmempool(), True)
            self.connect_nodes(0, 1)
            self.sync_blocks()
            self.expect_wallet_notify([(bump2, blockheight2, blockhash2), (tx2, -1, UNCONFIRMED_HASH_STRING)])
            assert_equal(self.nodes[1].gettransaction(bump2)["confirmations"], 1)

        # TODO: add test for `-alertnotify` large fork notifications

        self.log.info("test -shutdownnotify")
        self.stop_nodes()
        self.wait_until(lambda: os.path.isfile(self.shutdownnotify_file), timeout=10)

    def expect_wallet_notify(self, tx_details):
        self.wait_until(lambda: len(os.listdir(self.walletnotify_dir)) >= len(tx_details), timeout=10)
        # Should have no more and no less files than expected
        assert_equal(sorted(notify_outputname(self.wallet, tx_id) for tx_id, _, _ in tx_details), sorted(os.listdir(self.walletnotify_dir)))
        # Should now verify contents of each file
        for tx_id, blockheight, blockhash in tx_details:
            fname = os.path.join(self.walletnotify_dir, notify_outputname(self.wallet, tx_id))
            # Wait for the cached writes to hit storage
            self.wait_until(lambda: os.path.getsize(fname) > 0, timeout=10)
            with open(fname, 'rt', encoding='utf-8') as f:
                text = f.read()
                # Universal newline ensures '\n' on 'nt'
                assert_equal(text[-1], '\n')
                text = text[:-1]
                if platform.system() == 'Windows':
                    # On Windows, echo as above will append a whitespace
                    assert_equal(text[-1], ' ')
                    text = text[:-1]
                expected = str(blockheight) + '_' + blockhash
                assert_equal(text, expected)

        for tx_file in os.listdir(self.walletnotify_dir):
            os.remove(os.path.join(self.walletnotify_dir, tx_file))


if __name__ == '__main__':
    NotificationsTest(__file__).main()


Review comment (bug):
nit: isn't "at least" imprecise, and you need _more than_ 6 blocks?
The validation codes uses `>` instead of `>=` and the test fails if I create just 6 blocks on top of the tip.

Code after:
            assert_equal(tx2 in self.nodes[0].getrawmempool(), True)
            self.sync_mempools()
            self.expect_wallet_notify([(tx2, -1, UNCONFIRMED_HASH_STRING)])

            # Bump tx2 as bump2 and generate a block on node 0 while
            # disconnected, then reconnect and check for notifications on node 1
            # about newly confirmed bump2 and newly conflicted tx2.
            self.disconnect_nodes(0, 1)
            bump2 = self.nodes[0].bumpfee(tx2)["txid"]
            blockhash2 = self.generatetoaddress(self.nodes[0], 1, ADDRESS_BCRT1_UNSPENDABLE, sync_fun=self.no_op)[0]
            blockheight2 = self.nodes[0].getblockcount()
            assert_equal(self.nodes[0].gettransaction(bump2)["confirmations"], 1)
            assert_equal(tx2 in self.nodes[1].getrawmempool(), True)
            self.connect_nodes(0, 1)
            self.sync_blocks()
            self.expect_wallet_notify([(bump2, blockheight2, blockhash2), (tx2, -1, UNCONFIRMED_HASH_STRING)])
            assert_equal(self.nodes[1].gettransaction(bump2)["confirmations"], 1)

        self.log.info("test -alertnotify with large work invalid chain")
        # create a bunch of invalid blocks
        tip = self.nodes[0].getbestblockhash()
        height = self.nodes[0].getblockcount() + 1
        block_time = self.nodes[0].getblock(tip)['time'] + 1

        invalid_blocks = []
        for _ in range(7):  # invalid chain must be longer than 6 blocks to trigger warning
            block = create_block(int(tip, 16), create_coinbase(height), block_time)
            # make block invalid by exceeding block subsidy
            block.vtx[0].vout[0].nValue += 1
            block.hashMerkleRoot = block.calc_merkle_root()
            block.solve()
            invalid_blocks.append(block)
            tip = block.hash_hex
            height += 1
            block_time += 1

        # submit headers of invalid blocks
        for invalid_block in invalid_blocks:
            self.nodes[0].submitheader(invalid_block.serialize().hex())
        # submit invalid blocks in reverse order (tip first, to set m_best_invalid)
        for invalid_block in reversed(invalid_blocks):
            self.nodes[0].submitblock(invalid_block.serialize().hex())

        self.wait_until(lambda: os.path.isfile(self.alertnotify_file), timeout=10)
        self.wait_until(self.large_work_invalid_chain_warning_in_alert_file, timeout=10)

        self.log.info("test -shutdownnotify")
        self.stop_nodes()
        self.wait_until(lambda: os.path.isfile(self.shutdownnotify_file), timeout=10)

    def large_work_invalid_chain_warning_in_alert_file(self):