📝 Update testing events documentation (#13259)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Motov Yurii <109919500+YuriiMotov@users.noreply.github.com>
Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

tests/test_tutorial/test_testing/test_tutorial004.py

@@ -0,0 +1,5 @@
+from docs_src.app_testing.tutorial004 import test_read_items
+
+
+def test_main():
+    test_read_items()