Kata: Password validation in Python

Yesterday I did the Password validation kata in Python.

I used TDD to write the code.

These are the tests using Pytest:

	import pytest
	from password_validator import PasswordValidator
	@pytest.fixture
	def validator():
	return PasswordValidator(8)
	def test_a_strong_password(validator):
	assert validator.is_strong_password("#Ab3cccc") is True
	def test_that_only_passwords_with_the_minimum_length_are_strong(validator):
	assert validator.is_strong_password("#Ab3ccc") is False
	def test_that_only_passwords_including_numbers_are_strong(validator):
	assert validator.is_strong_password("#Abccccc") is False
	def test_that_only_passwords_including_upper_case_letters_are_strong(validator):
	assert validator.is_strong_password("#ab3cccc") is False
	def test_that_only_passwords_including_lower_case_letters_are_strong(validator):
	assert validator.is_strong_password("#AB3CCCC") is False
	def test_that_only_passwords_including_special_characters_are_strong(validator):
	assert validator.is_strong_password("cAb3cccc") is False

view raw password_validator_tests.py hosted with ❤ by GitHub

and this is the resulting code:

	import re
	class PasswordValidator(object):
	def __init__(self, minimum_length):
	self.minimum_length = minimum_length
	def is_strong_password(self, password):
	includes_special_characters = self._includes_any(
	self.REQUIRED_SPECIAL_CHARACTERS, password
	)
	includes_lower_case_letters = self._includes_any(
	self.LOWER_CASE_LETTERS, password
	)
	includes_upper_case_letters = self._includes_any(
	self.UPPER_CASE_LETTERS, password
	)
	includes_numbers = self._includes_any(self.NUMBERS, password)
	has_minimum_length = len(password) >= self.minimum_length
	return \
	has_minimum_length and \
	includes_numbers and \
	includes_upper_case_letters and \
	includes_lower_case_letters and \
	includes_special_characters
	@staticmethod
	def _includes_any(pattern, password):
	return re.search(pattern, password) is not None
	REQUIRED_SPECIAL_CHARACTERS = '[%#]'
	UPPER_CASE_LETTERS = '[A-Z]'
	LOWER_CASE_LETTERS = '[a-z]'
	NUMBERS = '[0-9]'

view raw password_validator.py hosted with ❤ by GitHub

If you want to follow the process step by step, have a look at the commits.

You can find all the code in GitHub.