qa: Add TestNode::assert_debug_log

Github-Pull: #14024
Rebased-From: fa3e9f7627

test/functional/p2p_invalid_tx.py

@@ -138,9 +138,14 @@ class InvalidTxRequestTest(BitcoinTestFramework):
         self.log.info('Test a transaction that is rejected, with BIP61 disabled')
         self.restart_node(0, ['-enablebip61=0', '-persistmempool=0'])
         self.reconnect_p2p(num_connections=1)
+        with node.assert_debug_log(expected_msgs=[
+                "{} from peer=0 was not accepted: mandatory-script-verify-flag-failed (Invalid OP_IF construction) (code 16)".format(tx1.hash),
+                "disconnecting peer=0",
+        ]):
             node.p2p.send_txs_and_test([tx1], node, success=False, expect_disconnect=True)
         # send_txs_and_test will have waited for disconnect, so we can safely check that no reject has been received
         assert_equal(node.p2p.reject_code_received, None)
 
+
 if __name__ == '__main__':
     InvalidTxRequestTest().main()

test/functional/test_framework/test_node.py

@@ -4,6 +4,7 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Class for bitcoind node under test"""
 
+import contextlib
 import decimal
 import errno
 from enum import Enum
@@ -229,6 +230,23 @@ class TestNode():
     def wait_until_stopped(self, timeout=BITCOIND_PROC_WAIT_TIMEOUT):
         wait_until(self.is_node_stopped, timeout=timeout)
 
+    @contextlib.contextmanager
+    def assert_debug_log(self, expected_msgs):
+        debug_log = os.path.join(self.datadir, 'regtest', 'debug.log')
+        with open(debug_log, encoding='utf-8') as dl:
+            dl.seek(0, 2)
+            prev_size = dl.tell()
+        try:
+            yield
+        finally:
+            with open(debug_log, encoding='utf-8') as dl:
+                dl.seek(prev_size)
+                log = dl.read()
+            print_log = " - " + "\n - ".join(log.splitlines())
+            for expected_msg in expected_msgs:
+                if re.search(re.escape(expected_msg), log, flags=re.MULTILINE) is None:
+                    self._raise_assertion_error('Expected message "{}" does not partially match log:\n\n{}\n\n'.format(expected_msg, print_log))
+
     def assert_start_raises_init_error(self, extra_args=None, expected_msg=None, match=ErrorMatch.FULL_TEXT, *args, **kwargs):
         """Attempt to start the node and expect it to raise an error.