> Could you do not use implicit adding of assets?

We can call this `self.course_fix.add_asset(self.transcript)` code in tests where do we really need assets and do that explicitly. For example:
```python
def test_cc_button_transcripts_and_sub_fields_empty(self):
    self.transcript = 'subs_OEoXaMPEzfM.srt.sjson'
    self.course_fix.add_asset(self.transcript)
    self.navigate_to_video()
    self.video.show_captions()

    # Verify that we see "Hi, welcome to Edx." text in the captions
    self.assertIn('Hi, welcome to Edx.', self.video.captions_text)
```