Is isogram

Read the guideline before start.

An isogram is a word that has no repeating letters, consecutive or non-consecutive.

Inside app/test_main.py, write tests for a function is_isogram that takes a string word, that contains only letters, and checks whether this word is an isogram.

Notes:

• for this task, the empty string is an isogram;
• function should be case-insensitive (M and m are considered the same letter).

Please note: you have to use pytest for writing tests.

Examples:

is_isogram('playgrounds') is True
is_isogram('look') is False
is_isogram('Adam') is False
is_isogram('') is True

Run pytest app/ to check if function pass your tests.

Run pytest --numprocesses=auto tests/ to check if your tests cover all boundary conditions and pass task tests.