Enforce proper line ending removal when reading alphabet

Fixes #2611

.travis.yml

@@ -7,11 +7,20 @@ before_cache:
 python:
   - "3.6"
 
+jobs:
+  include:
+    - stage: cardboard linter
       install:
         - pip install --upgrade cardboardlint pylint
-
       script:
         # Run cardboardlinter, in case of pull requests
         - if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then
             cardboardlinter --refspec $TRAVIS_BRANCH -n auto;
           fi
+    - stage: python unit tests
+      install:
+        - pip install --upgrade -r requirements_tests.txt
+      script:
+        - if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then
+            python -m unittest;
+          fi

requirements_tests.txt

@@ -0,0 +1 @@
+absl-py

util/test_data/alphabet_macos.txt

@@ -0,0 +1 @@
+a
b
c

util/test_data/alphabet_unix.txt

@@ -0,0 +1,3 @@
+a
+b
+c

util/test_data/alphabet_windows.txt

@@ -0,0 +1,4 @@
+a
+b
+c
+

util/test_text.py

@@ -0,0 +1,34 @@
+import unittest
+import os
+
+from .text import Alphabet
+
+class TestAlphabetParsing(unittest.TestCase):
+
+    def _ending_tester(self, file, expected):
+        alphabet = Alphabet(os.path.join(os.path.dirname(__file__), 'test_data', file))
+        label = ''
+        label_id = -1
+        for expected_label, expected_label_id in expected:
+            try:
+                label_id = alphabet.encode(expected_label)
+            except KeyError:
+                pass
+            self.assertEqual(label_id, [expected_label_id])
+            try:
+                label = alphabet.decode([expected_label_id])
+            except KeyError:
+                pass
+            self.assertEqual(label, expected_label)
+
+    def test_macos_ending(self):
+        self._ending_tester('alphabet_macos.txt', [('a', 0), ('b', 1), ('c', 2)])
+
+    def test_unix_ending(self):
+        self._ending_tester('alphabet_unix.txt', [('a', 0), ('b', 1), ('c', 2)])
+
+    def test_windows_ending(self):
+        self._ending_tester('alphabet_windows.txt', [('a', 0), ('b', 1), ('c', 2)])
+
+if __name__ == '__main__':
+    unittest.main()

util/text.py

@@ -1,6 +1,5 @@
 from __future__ import absolute_import, division, print_function
 
-import codecs
 import numpy as np
 import re
 import struct
@@ -15,7 +14,7 @@ class Alphabet(object):
         self._str_to_label = {}
         self._size = 0
         if config_file:
-            with codecs.open(config_file, 'r', 'utf-8') as fin:
+            with open(config_file, 'r', encoding='utf-8') as fin:
                 for line in fin:
                     if line[0:2] == '\\#':
                         line = '#\n'