Add explanation to __init__.py

Author: furtib

test/unit/__init__.py

@@ -19,5 +19,6 @@
 import os
 import sys
 
-# Setup the required environment variables for the tests.
+# Allow relative imports within the test project to work as expected
+# Without it no module (test) would be able to import the common library
 sys.path.append(os.path.join(os.path.dirname(os.path.abspath(__file__))))