Added preliminary tests.

regex-requirements.txt

@@ -0,0 +1 @@
+regex

tests/test_regex.py

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import
+
+import logging
+import unittest
+
+logging.basicConfig(level=logging.INFO)
+
+from lark.lark import Lark
+
+
+class TestRegex(unittest.TestCase):
+    def test_unicode_class(self):
+        "Tests that character classes from the `regex` module work correctly."
+        g = Lark(r"""
+                    ?start: NAME
+                    NAME: ID_START ID_CONTINUE*
+                    ID_START: /[\p{Lu}\p{Ll}\p{Lt}\p{Lm}\p{Lo}\p{Nl}_]+/
+                    ID_CONTINUE: ID_START | /[\p{Mn}\p{Mc}\p{Nd}\p{Pc}·]+/
+                """)
+
+        self.assertEqual(g.parse('வணக்கம்'), 'வணக்கம்')
+
+    def test_unicode_word(self):
+        "Tests that a persistent bug in the `re` module works when `regex` is enabled."
+        g = Lark(r"""
+                    ?start: NAME
+                    NAME: /[\w]+/
+                """)
+        self.assertEqual(g.parse('வணக்கம்'), 'வணக்கம்')
+
+
+if __name__ == '__main__':
+    unittest.main()

tox.ini

@@ -15,6 +15,7 @@ pypy3 = pypy3
 whitelist_externals = git
 deps =
     -rnearley-requirements.txt
+    -rregex-requirements.txt
 
 # to always force recreation and avoid unexpected side effects
 recreate=True