bugfix empty string to wcwidth() while we're here

bin/update-tables.py

@@ -24,7 +24,6 @@
 import logging
 import datetime
 import functools
-import collections
 import unicodedata
 from pathlib import Path
 from dataclasses import field, fields, dataclass

tests/test_core.py

@@ -41,6 +41,25 @@ def test_package_version():
     assert result == expected
 
 
+def test_empty_string():
+    """
+    Test empty string is OK.
+
+    https://github.com/jquast/wcwidth/issues/24
+    """
+    phrase = ""
+    expect_length_each = 0
+    expect_length_phrase = 0
+
+    # exercise,
+    length_each = wcwidth.wcwidth(phrase)
+    length_phrase = wcwidth.wcswidth(phrase)
+
+    # verify.
+    assert length_each == expect_length_each
+    assert length_phrase == expect_length_phrase
+
+
 def basic_string_type():
     """
     This is a python 2-specific test of the basic "string type"

wcwidth/wcwidth.py

@@ -134,7 +134,7 @@ def wcwidth(wc, unicode_version='auto'):
 
     See :ref:`Specification` for details of cell measurement.
     """
-    ucs = ord(wc)
+    ucs = ord(wc) if wc else 0
 
     # small optimization: early return of 1 for printable ASCII, this provides
     # approximately 40% performance improvement for mostly-ascii documents, with