Add child loggers validation test

tests/functional/test_logger_utils.py

@@ -6,6 +6,7 @@
 from enum import Enum
 
 import pytest
+from pytest_mock import MockerFixture
 
 from aws_lambda_powertools import Logger
 from aws_lambda_powertools.logging import formatter, utils
@@ -195,6 +196,33 @@ def test_copy_config_to_ext_loggers_should_not_break_append_keys(stdout, log_lev
     powertools_logger.append_keys(key="value")
 
 
+def test_copy_config_to_ext_loggers_child_loggers_work(stdout):
+    # GIVEN powertools logger AND  child initialized AND
+
+    # GIVEN Loggers are initialized
+    # create child logger before parent to mimick
+    # importing logger from another module/file
+    # as loggers are created in global scope
+    service = service_name()
+    child = Logger(stream=stdout, service=service, child=True)
+    parent = Logger(stream=stdout, service=service)
+
+    # WHEN a child Logger adds an additional key
+    child.structure_logs(append=True, customer_id="value")
+
+    # WHEN configuration copied from powertools logger
+    # AND powertools logger and child logger used
+    utils.copy_config_to_registered_loggers(source_logger=parent)
+    parent.warning("Logger message")
+    child.warning("Child logger message")
+
+    # THEN payment_id key added to both powertools logger and child logger
+    parent_log, child_log = capture_multiple_logging_statements_output(stdout)
+    assert "customer_id" in parent_log
+    assert "customer_id" in child_log
+    assert child.parent.name == service
+
+
 def test_copy_config_to_ext_loggers_no_duplicate_logs(stdout, logger, log_level):
     # GIVEN an root logger, external logger and powertools logger initialized