Is Valid Email Kata

Write a Python function that returns True or False to indicate whether the passed value is a valid email address or not.

Tests

tests/test_is_email.py

  import unittest
  import parameterized

  from ..validators import is_email

  class TestIsEmailFunction(unittest.TestCase):
      @parameterized.parameterized.expand([
          ('value is simple email address', 'example@example.com'),
          ('domian is a subdomain', 'example@subdomain.domain.com'),
          ('domain contains dashes', 'example@example-domain.com'),
          ('username contains digits', 'example123@example.com'),
      ])
      def test_should_return_true_when(self, name, value):
          self.assertTrue(is_email(value))

      @parameterized.parameterized.expand([
          ('domain is empty', 'example@'),
          ('host is empty', 'example@.com'),
          ('at character is missing', 'example.com'),
          ('domain ends with period', 'example@com.'),
          ('domain starts with period', 'example@.domain.com'),
          ('username is empty', '@domain.com'),
      ])
      def test_should_return_false_when(self, name, value):
          self.assertFalse(is_email(value))

Solution 1

validator.py

import re

def is_email(value):
   pattern = r'^[a-zA-Z0-9._%+-]+@([a-zA-Z0-9-]+\.)+[a-zA-Z]{2,}$'

   regex = re.compile(pattern)
   match = regex.search(value)

   return bool(match)