[Housekeeping] Improve test stability (#232)

* Ensured all tests use at least the DataCase module

* addressed one flakey test

* More flakey tests

* Consolidated Mox usage

test/pinchflat/fast_indexing/fast_indexing_helpers_test.exs

@@ -1,7 +1,6 @@
 defmodule Pinchflat.FastIndexing.FastIndexingHelpersTest do
   use Pinchflat.DataCase
 
-  import Mox
   import Pinchflat.MediaFixtures
   import Pinchflat.SourcesFixtures
   import Pinchflat.ProfilesFixtures
@@ -11,8 +10,6 @@ defmodule Pinchflat.FastIndexing.FastIndexingHelpersTest do
   alias Pinchflat.Downloading.MediaDownloadWorker
   alias Pinchflat.FastIndexing.FastIndexingHelpers
 
-  setup :verify_on_exit!
-
   describe "kickoff_download_tasks_from_youtube_rss_feed/1" do
     setup do
       stub(YtDlpRunnerMock, :run, fn _url, _opts, _ot ->