Add support for caseless assertions that also work with unicode through mixin.

caseless_assertions.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import unittest
import unicodedata

''' There is text for which text.lower() != text.upper().lower(), such as "ß":

"ß".lower()
#>>> 'ß'

"ß".upper().lower()
#>>> 'ss'

http://stackoverflow.com/a/29247821
'''


def normalize_caseless(text):
    return unicodedata.normalize("NFKD", text.casefold())

def caseless_equal(left, right):
    return normalize_caseless(left) == normalize_caseless(right)


class CaselessAssertions:
    def assertCaselessEqual(self, left, right):
        self.assertEqual(normalize_caseless(left), normalize_caseless(right))

    def assertCaselessDictEqual(self, left, right):
        left = {normalize_caseless(k): v for k, v in left.items()}
        right = {normalize_caseless(k): v for k, v in right.items()}
        self.assertDictEqual(left, right)


class CaselessTests(unittest.TestCase, CaselessAssertions):

    def test_equal(self):
        self.assertCaselessEqual("Test", "test")

    def test_equal_fail(self):
        self.assertCaselessEqual("Test", "testx")

    def test_dict(self):
        d1 = {'X': 3, 'Y': 2}
        d2 = {'y': 2, 'x': 3}
        self.assertCaselessDictEqual(d1, d2)

    def test_dict_fail_value(self):
        d1 = {'X': 3, 'Y': 2}
        d2 = {'y': 3, 'x': 3}
        self.assertCaselessDictEqual(d1, d2)

    def test_dict_fail_key(self):
        d1 = {'X': 3, 'Y': 2}
        d2 = {'y': 2, 'a': 3}
        self.assertCaselessDictEqual(d1, d2)

    def test_unicode(self):
        d1 = {'ß': 42, '💾💿': 11}
        d2 = {'ß': 42, '💾💿': 11}
        self.assertCaselessDictEqual(d1, d2)

if __name__ == '__main__':
    unittest.main()


''' OUTPUT
.FF.F.
======================================================================
FAIL: test_dict_fail_key (__main__.CaselessTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "Spielwiese/caseless.py", line 44, in test_dict_fail_key
    self.assertCaselessDictEqual(d1, d2)
  File "Spielwiese/caseless.py", line 21, in assertCaselessDictEqual
    self.assertDictEqual(left, right)
AssertionError: {'x': 3, 'y': 2} != {'a': 3, 'y': 2}
- {'x': 3, 'y': 2}
?   ^

+ {'a': 3, 'y': 2}
?   ^


======================================================================
FAIL: test_dict_fail_value (__main__.CaselessTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "Spielwiese/caseless.py", line 39, in test_dict_fail_value
    self.assertCaselessDictEqual(d1, d2)
  File "Spielwiese/caseless.py", line 21, in assertCaselessDictEqual
    self.assertDictEqual(left, right)
AssertionError: {'x': 3, 'y': 2} != {'x': 3, 'y': 3}
- {'x': 3, 'y': 2}
?               ^

+ {'x': 3, 'y': 3}
?               ^


======================================================================
FAIL: test_equal_fail (__main__.CaselessTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "Spielwiese/caseless.py", line 29, in test_equal_fail
    self.assertCaselessEqual("Test", "testx")
  File "Spielwiese/caseless.py", line 16, in assertCaselessEqual
    self.assertEqual(normalize_caseless(left), normalize_caseless(right))
AssertionError: 'test' != 'testx'
- test
+ testx
?     +


----------------------------------------------------------------------
Ran 6 tests in 0.005s

FAILED (failures=3)
'''