After installing, running input-tester does input-tester: command not found. Similarly for all other commands. Refreshing / opening new terminal does not help.
A simple workaround would be to execute it as python3 -m input_tool.input_tester. Sadly the scripts have '-' in their name so this is not possible (or one needs some arcane python magic to invoke a module with a '-' in its name). Though I am not sure if this is enough -- it would be if input_tool were a "regular python package" but not sure if it is / what stuff does setup.py do.