From 46bc9b7d7cea2e161670e65abe42ef01d39e8957 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sergey=20M=E2=80=A4?= <dstftw@gmail.com>
Date: Thu, 19 May 2016 04:31:30 +0600
Subject: [PATCH] [utils] Allow None in remove_{start,end}

---
 test/test_utils.py  | 12 ++++++++++++
 youtube_dl/utils.py |  8 ++------
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/test/test_utils.py b/test/test_utils.py
index 520d32ff50..a697232a8b 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -50,6 +50,8 @@
     sanitize_path,
     prepend_extension,
     replace_extension,
+    remove_start,
+    remove_end,
     remove_quotes,
     shell_quote,
     smuggle_url,
@@ -215,6 +217,16 @@ def test_replace_extension(self):
         self.assertEqual(replace_extension('.abc', 'temp'), '.abc.temp')
         self.assertEqual(replace_extension('.abc.ext', 'temp'), '.abc.temp')
 
+    def test_remove_start(self):
+        self.assertEqual(remove_start(None, 'A - '), None)
+        self.assertEqual(remove_start('A - B', 'A - '), 'B')
+        self.assertEqual(remove_start('B - A', 'A - '), 'B - A')
+
+    def test_remove_end(self):
+        self.assertEqual(remove_end(None, ' - B'), None)
+        self.assertEqual(remove_end('A - B', ' - B'), 'A')
+        self.assertEqual(remove_end('B - A', ' - B'), 'B - A')
+
     def test_remove_quotes(self):
         self.assertEqual(remove_quotes(None), None)
         self.assertEqual(remove_quotes('"'), '"')
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index ac60ba18cd..5301d07404 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -1549,15 +1549,11 @@ def setproctitle(title):
 
 
 def remove_start(s, start):
-    if s.startswith(start):
-        return s[len(start):]
-    return s
+    return s[len(start):] if s is not None and s.startswith(start) else s
 
 
 def remove_end(s, end):
-    if s.endswith(end):
-        return s[:-len(end)]
-    return s
+    return s[:-len(end)] if s is not None and s.endswith(end) else s
 
 
 def remove_quotes(s):