Allow uppercase transcripts srt extension.

cms/djangoapps/contentstore/tests/test_transcripts_utils.py

@@ -308,8 +308,9 @@ class TestGenerateSubsFromSource(TestDownloadYoutubeSubs):
         """)
         self.clear_subs_content(youtube_subs)
 
-        # Check transcripts_utils.TranscriptsGenerationException not thrown
-        transcripts_utils.generate_subs_from_source(youtube_subs, 'srt', srt_filedata, self.course)
+        # Check transcripts_utils.TranscriptsGenerationException not thrown.
+        # Also checks that uppercase file extensions are supported.
+        transcripts_utils.generate_subs_from_source(youtube_subs, 'SRT', srt_filedata, self.course)
 
         # Check assets status after importing subtitles.
         for subs_id in youtube_subs.values():

common/lib/xmodule/xmodule/video_module/transcripts_utils.py

@@ -213,7 +213,7 @@ def generate_subs_from_source(speed_subs, subs_type, subs_filedata, item, langua
     :returns: True, if all subs are generated and saved successfully.
     """
     _ = item.runtime.service(item, "i18n").ugettext
-    if subs_type != 'srt':
+    if subs_type.lower() != 'srt':
         raise TranscriptsGenerationException(_("We support only SubRip (*.srt) transcripts format."))
     try:
         srt_subs_obj = SubRipFile.from_string(subs_filedata)