added coveraged around utils

tests/test_utils.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env/python
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+from nose.tools import eq_
+from pytube import utils
+
+
+class TestUtils(object):
+    blob = "Lorem ipsum dolor sit amet, consectetur adipiscing elit"
+
+    def test_truncate(self):
+        """Truncate string works as expected"""
+        truncated = utils.truncate(self.blob, 11)
+        eq_(truncated, 'Lorem ipsum')
+
+    def test_safe_filename(self):
+        """Unsafe characters get stripped from generated filename"""
+        eq_(utils.safe_filename("abc1245$$"), "abc1245")
+        eq_(utils.safe_filename("abc##"), "abc")
+        eq_(utils.safe_filename("abc:foo"), "abc -foo")
+        eq_(utils.safe_filename("abc_foo"), "abc foo")