Fix ModuleNotFoundError in advanced_operations tests

The tests in `examples/advanced_operations/tests/` were failing
with `ModuleNotFoundError: No module named 'examples'` because
the project root directory was not in Python's `sys.path` during
test execution.

This commit fixes the issue by adding a code snippet at the
beginning of each affected test file. This snippet calculates
the path to the project root (three levels above the test file's
directory) and inserts it into `sys.path`.

This ensures that the `examples` package can be correctly imported
regardless of the working directory from which pytest is invoked.

All tests in `examples/advanced_operations/tests/` now pass after
this change.

Author: google-labs-jules[bot]

examples/advanced_operations/tests/test_add_demand_gen_campaign.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_add_dynamic_page_feed_asset.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_add_smart_campaign.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_create_and_attach_shared_keyword_set.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_find_and_remove_criteria_from_shared_set.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_get_ad_group_bid_modifiers.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_use_cross_account_bidding_strategy.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys

examples/advanced_operations/tests/test_use_portfolio_bidding_strategy.py

@@ -1,3 +1,12 @@
+import sys
+import os
+# Calculate the path to the project root directory
+# __file__ is examples/advanced_operations/tests/test_name.py
+# project_root is three levels up from the test file's directory
+project_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+if project_root not in sys.path:
+    sys.path.insert(0, project_root)
+
 import unittest
 from unittest import mock
 import sys