Addeded utility function for combining unicode normalization and casefolding into a single step

Also:
- Updated the alphabetical sort utility function to use this
- Started adding explicit unit tests for functions in utils.py

Author: tleonhardt

cmd2/utils.py

@@ -5,6 +5,7 @@
 import collections
 import os
 from typing import Any, List, Optional, Union
+import unicodedata
 
 from . import constants
 
@@ -110,7 +111,7 @@ def which(editor: str) -> Optional[str]:
 
 
 def is_text_file(file_path: str) -> bool:
-    """Returns if a file contains only ASCII or UTF-8 encoded text
+    """Returns if a file contains only ASCII or UTF-8 encoded text.
 
     :param file_path: path to the file being checked
     :return: True if the file is a text file, False if it is binary.
@@ -147,8 +148,8 @@ def is_text_file(file_path: str) -> bool:
 
 
 def remove_duplicates(list_to_prune: List) -> List:
-    """
-    Removes duplicates from a list while preserving order of the items
+    """Removes duplicates from a list while preserving order of the items.
+
     :param list_to_prune: the list being pruned of duplicates
     :return: The pruned list
     """
@@ -159,10 +160,19 @@ def remove_duplicates(list_to_prune: List) -> List:
     return list(temp_dict.keys())
 
 
-def alphabetical_sort(list_to_sort: List[str]) -> List[str]:
+def norm_fold(astr: str) -> str:
+    """Normalize and casefold Unicode strings for saner comparisons.
+
+    :param astr: input unicode string
+    :return: a normalized and case-folded version of the input string
     """
-    Sorts a list of strings alphabetically
+    return unicodedata.normalize('NFC', astr).casefold()
+
+
+def alphabetical_sort(list_to_sort: List[str]) -> List[str]:
+    """Sorts a list of strings alphabetically.
+
     :param list_to_sort: the list being sorted
     :return: the sorted list
     """
-    return sorted(list_to_sort, key=str.casefold)
+    return sorted(list_to_sort, key=norm_fold)

tests/test_utils.py

@@ -0,0 +1,16 @@
+# coding=utf-8
+"""
+Unit/functional testing for cmd2/utils.py module.
+
+Copyright 2018 Todd Leonhardt <[email protected]>
+Released under MIT license, see LICENSE file
+"""
+from colorama import Fore
+import cmd2.utils as cu
+
+
+def test_strip_ansi():
+    base_str = 'Hello, world!'
+    ansi_str =  Fore.GREEN + base_str + Fore.RESET
+    assert base_str != ansi_str
+    assert base_str == cu.strip_ansi(ansi_str)