Add tests and planning doc

nw.py

@@ -1,13 +1,14 @@
-# cli.py
+# nw.py
 # ------
 # Implements a simple number-to-text command-line interface.
+# Ex: python nw.py 145
 
 from argparse import ArgumentParser
-from numberwords import int_under_1000000_to_text
+from numberwords import int_under_1000000_to_str
 
 parser = ArgumentParser("Print out a number as it is spoken in English.")
 parser.add_argument("number", type=int)
 args = parser.parse_args()
-text = int_under_1000000_to_text(args.number)
+text = int_under_1000000_to_str(args.number)
 print(text)