diff --git a/README.org b/README.org
index ecf9a3a..f3e91c8 100644
--- a/README.org
+++ b/README.org
@@ -212,6 +212,7 @@ if __name__ == "__main__":
     main()
 #+end_src
 * Unit testing
+The following code blocks are tangled into test.py.
 ** Imports
 #+begin_src python :tangle test.py
 import unittest