Architecture

Testapp is a Python CLI built around a REPL (Read-Eval-Print Loop).

Structure

src/
  __init__.py     — package marker
  main.py         — entry point; contains the REPL loop
  commands.py     — command registry and handlers
tests/
  __init__.py
  test_commands.py
  test_main.py
requirements.txt  — pytest (dev)

Command registry

src/commands.py defines two things:

COMMAND_DESCRIPTIONS — {name: one-line description} used by help
COMMANDS — {name: callable} mapping command names to handler functions

Every handler takes no arguments and returns a string. The REPL prints that string.

To add a new command:

Define a handler function _my_command() -> str
Add it to COMMAND_DESCRIPTIONS with a description
Add it to COMMANDS under its name

REPL loop (`src/main.py`)

print welcome message
loop:
  print "> " prompt
  read input → strip whitespace → lowercase
  if empty: skip
  if in COMMANDS: call handler, print result
  else: print "Unknown command" error
  on KeyboardInterrupt: exit loop cleanly