fix(test): Randomly sample transactions for test runs (#22487)

src/sentry/utils/pytest/sentry.py

@@ -1,5 +1,7 @@
 from __future__ import absolute_import
 
+import pytest
+
 from sentry.utils.compat import mock
 import os
 from hashlib import md5
@@ -242,6 +244,7 @@ def pytest_collection_modifyitems(config, items):
 
     - Filter tests that subclass SnubaTestCase as tests in `tests/acceptance` are not being marked as `snuba`
     - Select tests based on group and group strategy
+    - Configure pytest-sentry
 
     """
 
@@ -288,3 +291,6 @@ def pytest_collection_modifyitems(config, items):
     if len(discard) > 0:
         items[:] = keep
         config.hook.pytest_deselected(items=discard)
+
+    for item in items:
+        item.add_marker(pytest.mark.sentry_client({"traces_sample_rate": 0.1}))