Merge branch 'dot-env' into dev

Author: rayluo

.gitignore

@@ -57,3 +57,5 @@ docs/_build/
 # The test configuration file(s) could potentially contain credentials
 tests/config.json
 
+
+.env

requirements.txt

@@ -1 +1,2 @@
 .
+python-dotenv

tests/test_e2e.py

@@ -1,3 +1,16 @@
+"""If the following ENV VAR are available, many end-to-end test cases would run.
+LAB_APP_CLIENT_SECRET=...
+LAB_OBO_CLIENT_SECRET=...
+LAB_APP_CLIENT_ID=...
+LAB_OBO_PUBLIC_CLIENT_ID=...
+LAB_OBO_CONFIDENTIAL_CLIENT_ID=...
+"""
+try:
+    from dotenv import load_dotenv  # Use this only in local dev machine
+    load_dotenv()  # take environment variables from .env.
+except:
+    pass
+
 import logging
 import os
 import json