diff --git a/.circleci/config.yml b/.circleci/config.yml
old mode 100755
new mode 100644
index c2a710b..56248af
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,3 +1,14 @@
+# WARNING: Minimize edits to this file!
+#
+# This file is part of the CI infrastructure for the StackStorm-Exchange.
+# As such, it gets overwritten periodically in CI infrastructure updates.
+# Check out `tests/setup_testing_env.sh` for how to customize the test env.
+# If you to add jobs, docker images, or other changes that do not work in
+# `tests/setup_testing_env.sh`, then please add what you need and avoid
+# changing the standard build_and_test and deploy jobs.
+#
+# Thanks for your contribution!
+---
 version: 2
 
 jobs:
diff --git a/tests/setup_testing_env.sh b/tests/setup_testing_env.sh
new file mode 100644
index 0000000..99c67f8
--- /dev/null
+++ b/tests/setup_testing_env.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# For python deps, please use requirements.txt or requirements-test.txt.
+# Do not install python requirements with this script.
+
+# Some packs need to install and configure additional packages to properly
+# run their test suite. Other packs need to clone other repositories to
+# reuse standardized testing infrastructure. And other functional or end-to-end
+# tests might need additional system setup to access external APIs via
+# an enterprise bus or something else.
+# That is the purpose of this script. Setup the testing environment
+# to do mock-less regression or end-to-end testing.
+
+# This script is called by `deployment` housed in StackStorm-exchange/ci.
+# `deployment` will only run this script if it is executable.