convert: playlist: M3U read as bytes

- M3UFile.read() method reads in rb mode.
- M3UFile.read() method handles removal of (platform specific) line endings.
- Playlist contents and EXTM3U header is handled as bytes.
- Fix test_playlist*read* tests to encode playlist UTF-8 assert strings to
  bytes using bytestring_path() before comparision.
  - Fixture playlist_windows.m3u8 is now actually Windows formatted (\r\n + BOM)

beets/util/m3u.py

@@ -42,18 +42,18 @@ class M3UFile():
         """Reads the m3u file from disk and sets the object's attributes."""
         pl_normpath = normpath(self.path)
         try:
-            with open(syspath(pl_normpath), "r", encoding="utf-8") as pl_file:
+            with open(syspath(pl_normpath), "rb") as pl_file:
                 raw_contents = pl_file.readlines()
         except OSError as exc:
             raise FilesystemError(exc, 'read', (pl_normpath, ),
                                   traceback.format_exc())
 
-        self.extm3u = True if raw_contents[0] == "#EXTM3U\n" else False
+        self.extm3u = True if raw_contents[0].rstrip() == b"#EXTM3U" else False
         for line in raw_contents[1:]:
-            if line.startswith("#"):
-                # Some EXTM3U comment, do something. FIXME
+            if line.startswith(b"#"):
+                # Support for specific EXTM3U comments could be added here.
                 continue
-            self.media_list.append(syspath(line, prefix=False))
+            self.media_list.append(normpath(line.rstrip()))
         if not self.media_list:
             raise EmptyPlaylistError
 

test/rsrc/playlist_windows.m3u8

@@ -1,3 +1,3 @@
-#EXTM3U
-x:\This\is\å\path\to_a_file.mp3
-x:\This\is\another\path\tö_a_file.mp3
+#EXTM3U
+x:\This\is\å\path\to_a_file.mp3
+x:\This\is\another\path\tö_a_file.mp3

test/test_m3ufile.py

@@ -90,13 +90,14 @@ class M3UFileTest(unittest.TestCase):
         )
         rmtree(tempdir)
 
+    @unittest.skipIf(sys.platform == 'win32', 'win32')
     def test_playlist_load_ascii(self):
         """Test loading ascii paths from a playlist file."""
         the_playlist_file = path.join(RSRC, b'playlist.m3u')
         m3ufile = M3UFile(the_playlist_file)
         m3ufile.load()
         self.assertEqual(m3ufile.media_list[0],
-                         '/This/is/a/path/to_a_file.mp3\n')
+                         bytestring_path('/This/is/a/path/to_a_file.mp3'))
 
     @unittest.skipIf(sys.platform == 'win32', 'win32')
     def test_playlist_load_unicode(self):
@@ -105,18 +106,19 @@ class M3UFileTest(unittest.TestCase):
         m3ufile = M3UFile(the_playlist_file)
         m3ufile.load()
         self.assertEqual(m3ufile.media_list[0],
-                         '/This/is/å/path/to_a_file.mp3\n')
+                         bytestring_path('/This/is/å/path/to_a_file.mp3'))
 
     @unittest.skipUnless(sys.platform == 'win32', 'win32')
     def test_playlist_load_unicode_windows(self):
         """Test loading unicode paths from a playlist file."""
         the_playlist_file = path.join(RSRC, b'playlist_windows.m3u8')
-        winpath = path.join('x:\\', 'This', 'is', 'å', 'path', 'to_a_file.mp3')
+        winpath = bytestring_path(path.join(
+            'x:\\', 'This', 'is', 'å', 'path', 'to_a_file.mp3'))
         m3ufile = M3UFile(the_playlist_file)
         m3ufile.load()
         self.assertEqual(
             m3ufile.media_list[0],
-            winpath + '\n'
+            winpath
         )
 
     def test_playlist_load_extm3u(self):