Add unittest.

tests/test_error_rate.py

+# -*- coding: utf-8 -*-
+import unittest
+import sys
+sys.path.append('..')
+import error_rate
+
+
+class TestParse(unittest.TestCase):
+    def test_wer(self):
+        ref = 'i UM the PHONE IS i LEFT THE portable PHONE UPSTAIRS last night'
+        hyp = 'i GOT IT TO the FULLEST i LOVE TO portable FROM OF STORES last night'
+        word_error_rate = error_rate.wer(ref, hyp)
+        self.assertTrue(abs(word_error_rate - 0.769230769231) < 1e-6)
+
+    def test_cer_en(self):
+        ref = 'werewolf'
+        hyp = 'weae  wolf'
+        char_error_rate = error_rate.cer(ref, hyp)
+        self.assertTrue(abs(char_error_rate - 0.25) < 1e-6)
+
+    def test_cer_zh(self):
+        ref = u'我是中国人'
+        hyp = u'我是 美洲人'
+        char_error_rate = error_rate.cer(ref, hyp)
+        self.assertTrue(abs(char_error_rate - 0.6) < 1e-6)
+
+
+if __name__ == '__main__':
+    unittest.main()