diff --git a/test/plugins/test_art.py b/test/plugins/test_art.py
index fc85cc8e9..3c8411bc1 100644
--- a/test/plugins/test_art.py
+++ b/test/plugins/test_art.py
@@ -442,7 +442,7 @@ class ITunesStoreTest(UseThePlugin):
         with capture_log("beets.test_art") as logs:
             with self.assertRaises(StopIteration):
                 next(self.source.get(self.album, self.settings, []))
-        self.assertIn(expected, logs[1])
+        assert expected in logs[1]
 
     def test_itunesstore_requestexception(self):
         responses.add(
@@ -456,7 +456,7 @@ class ITunesStoreTest(UseThePlugin):
         with capture_log("beets.test_art") as logs:
             with self.assertRaises(StopIteration):
                 next(self.source.get(self.album, self.settings, []))
-        self.assertIn(expected, logs[1])
+        assert expected in logs[1]
 
     def test_itunesstore_fallback_match(self):
         json = """{
@@ -489,7 +489,7 @@ class ITunesStoreTest(UseThePlugin):
         with capture_log("beets.test_art") as logs:
             with self.assertRaises(StopIteration):
                 next(self.source.get(self.album, self.settings, []))
-        self.assertIn(expected, logs[1])
+        assert expected in logs[1]
 
     def test_itunesstore_returns_no_result_when_error_received(self):
         json = '{"error": {"errors": [{"reason": "some reason"}]}}'
@@ -499,7 +499,7 @@ class ITunesStoreTest(UseThePlugin):
         with capture_log("beets.test_art") as logs:
             with self.assertRaises(StopIteration):
                 next(self.source.get(self.album, self.settings, []))
-        self.assertIn(expected, logs[1])
+        assert expected in logs[1]
 
     def test_itunesstore_returns_no_result_with_malformed_response(self):
         json = """bla blup"""
@@ -509,7 +509,7 @@ class ITunesStoreTest(UseThePlugin):
         with capture_log("beets.test_art") as logs:
             with self.assertRaises(StopIteration):
                 next(self.source.get(self.album, self.settings, []))
-        self.assertIn(expected, logs[1])
+        assert expected in logs[1]
 
 
 class GoogleImageTest(UseThePlugin):
@@ -584,7 +584,7 @@ class CoverArtArchiveTest(UseThePlugin, CAAHelper):
         candidates = list(self.source.get(album, self.settings, []))
         self.assertEqual(len(candidates), 3)
         for candidate in candidates:
-            self.assertIn(f"-{maxwidth}.jpg", candidate.url)
+            assert f"-{maxwidth}.jpg" in candidate.url
 
     def test_caa_finds_image_if_maxwidth_is_set_and_thumbnails_is_empty(self):
         # CAA provides pre-sized thumbnails of width 250px, 500px, and 1200px
diff --git a/test/plugins/test_bareasc.py b/test/plugins/test_bareasc.py
index 393d686c8..0467f0270 100644
--- a/test/plugins/test_bareasc.py
+++ b/test/plugins/test_bareasc.py
@@ -71,7 +71,7 @@ class BareascPluginTest(PluginTestCase):
         with capture_stdout() as output:
             self.run_command("bareasc", "with accents")
 
-        self.assertIn("Antonin Dvorak", output.getvalue())
+        assert "Antonin Dvorak" in output.getvalue()
 
     def test_bareasc_format_output(self):
         """Bare-ASCII version of list -f command - check output."""
diff --git a/test/plugins/test_discogs.py b/test/plugins/test_discogs.py
index 416ca0276..ad24bab67 100644
--- a/test/plugins/test_discogs.py
+++ b/test/plugins/test_discogs.py
@@ -364,7 +364,7 @@ class DGAlbumInfoTest(BeetsTestCase):
             d = DiscogsPlugin().get_album_info(release)
 
         self.assertEqual(d, None)
-        self.assertIn("Release does not contain the required fields", logs[0])
+        assert "Release does not contain the required fields" in logs[0]
 
     def test_album_for_id(self):
         """Test parsing for a valid Discogs release_id"""
diff --git a/test/plugins/test_edit.py b/test/plugins/test_edit.py
index 5f1260ba9..adb4fb1a4 100644
--- a/test/plugins/test_edit.py
+++ b/test/plugins/test_edit.py
@@ -411,7 +411,7 @@ class EditDuringImporterNonSingletonTest(EditDuringImporterTestCase):
         assert all("match " in i.mb_trackid for i in self.lib.items())
 
         # Ensure album is fetched from a candidate.
-        self.assertIn("albumid", self.lib.albums()[0].mb_albumid)
+        assert "albumid" in self.lib.albums()[0].mb_albumid
 
     def test_edit_retag_apply(self):
         """Import the album using a candidate, then retag and edit and apply
@@ -439,7 +439,7 @@ class EditDuringImporterNonSingletonTest(EditDuringImporterTestCase):
         assert all("match " in i.mb_trackid for i in self.lib.items())
 
         # Ensure album is fetched from a candidate.
-        self.assertIn("albumid", self.lib.albums()[0].mb_albumid)
+        assert "albumid" in self.lib.albums()[0].mb_albumid
 
     def test_edit_discard_candidate(self):
         """Edit the album field for all items in the library, discard changes,
@@ -458,7 +458,7 @@ class EditDuringImporterNonSingletonTest(EditDuringImporterTestCase):
         assert all("match " in i.mb_trackid for i in self.lib.items())
 
         # Ensure album is fetched from a candidate.
-        self.assertIn("albumid", self.lib.albums()[0].mb_albumid)
+        assert "albumid" in self.lib.albums()[0].mb_albumid
 
     def test_edit_apply_candidate_singleton(self):
         """Edit the album field for all items in the library, apply changes,
diff --git a/test/plugins/test_export.py b/test/plugins/test_export.py
index 374c2529d..a96f08e70 100644
--- a/test/plugins/test_export.py
+++ b/test/plugins/test_export.py
@@ -52,7 +52,7 @@ class ExportPluginTest(PluginTestCase):
         out = self.execute_command(format_type="json", artist=item1.artist)
         json_data = json.loads(out)[0]
         for key, val in self.test_values.items():
-            self.assertIn(key, json_data)
+            assert key in json_data
             self.assertEqual(val, json_data[key])
 
     def test_jsonlines_output(self):
@@ -60,7 +60,7 @@ class ExportPluginTest(PluginTestCase):
         out = self.execute_command(format_type="jsonlines", artist=item1.artist)
         json_data = json.loads(out)
         for key, val in self.test_values.items():
-            self.assertIn(key, json_data)
+            assert key in json_data
             self.assertEqual(val, json_data[key])
 
     def test_csv_output(self):
@@ -82,5 +82,5 @@ class ExportPluginTest(PluginTestCase):
             for details in track:
                 tag = details.tag
                 txt = details.text
-                self.assertIn(tag, self.test_values, msg=tag)
+                assert tag in self.test_values, tag
                 self.assertEqual(self.test_values[tag], txt, msg=txt)
diff --git a/test/plugins/test_hook.py b/test/plugins/test_hook.py
index 71c33a705..c531cd8c6 100644
--- a/test/plugins/test_hook.py
+++ b/test/plugins/test_hook.py
@@ -44,26 +44,24 @@ class HookLogsTest(HookTestCase):
 
     def test_hook_empty_command(self):
         with self._configure_logs("") as logs:
-            self.assertIn('hook: invalid command ""', logs)
+            assert 'hook: invalid command ""' in logs
 
     # FIXME: fails on windows
     @unittest.skipIf(sys.platform == "win32", "win32")
     def test_hook_non_zero_exit(self):
         with self._configure_logs('sh -c "exit 1"') as logs:
-            self.assertIn(
-                "hook: hook for test_event exited with status 1", logs
-            )
+            assert "hook: hook for test_event exited with status 1" in logs
 
     def test_hook_non_existent_command(self):
         with self._configure_logs("non-existent-command") as logs:
             logs = "\n".join(logs)
 
-        self.assertIn("hook: hook for test_event failed: ", logs)
+        assert "hook: hook for test_event failed: " in logs
         # The error message is different for each OS. Unfortunately the text is
         # different in each case, where the only shared text is the string
         # 'file' and substring 'Err'
-        self.assertIn("Err", logs)
-        self.assertIn("file", logs)
+        assert "Err" in logs
+        assert "file" in logs
 
 
 class HookCommandTest(HookTestCase):
diff --git a/test/plugins/test_importfeeds.py b/test/plugins/test_importfeeds.py
index b988a8d4a..5f1f915ad 100644
--- a/test/plugins/test_importfeeds.py
+++ b/test/plugins/test_importfeeds.py
@@ -29,7 +29,7 @@ class ImportfeedsTestTest(BeetsTestCase):
         )
         assert playlist_path.endswith("album_name.m3u")
         with open(playlist_path) as playlist:
-            self.assertIn(item_path, playlist.read())
+            assert item_path in playlist.read()
 
     def test_playlist_in_subdir(self):
         config["importfeeds"]["formats"] = "m3u"
@@ -65,4 +65,4 @@ class ImportfeedsTestTest(BeetsTestCase):
         playlist = os.path.join(self.feeds_dir, f"imports_{date}.m3u")
         assert os.path.isfile(playlist)
         with open(playlist) as playlist_contents:
-            self.assertIn(item_path, playlist_contents.read())
+            assert item_path in playlist_contents.read()
diff --git a/test/plugins/test_info.py b/test/plugins/test_info.py
index 102aceb83..91778ed47 100644
--- a/test/plugins/test_info.py
+++ b/test/plugins/test_info.py
@@ -33,10 +33,10 @@ class InfoTest(PluginTestCase):
         mediafile.save()
 
         out = self.run_with_output("info", path)
-        self.assertIn(displayable_path(path), out)
-        self.assertIn("albumartist: AAA", out)
-        self.assertIn("disctitle: DDD", out)
-        self.assertIn("genres: a; b; c", out)
+        assert displayable_path(path) in out
+        assert "albumartist: AAA" in out
+        assert "disctitle: DDD" in out
+        assert "genres: a; b; c" in out
         self.assertNotIn("composer:", out)
 
     def test_item_query(self):
@@ -47,8 +47,8 @@ class InfoTest(PluginTestCase):
         item1.store()
 
         out = self.run_with_output("info", "album:yyyy")
-        self.assertIn(displayable_path(item1.path), out)
-        self.assertIn("album: xxxx", out)
+        assert displayable_path(item1.path) in out
+        assert "album: xxxx" in out
 
         self.assertNotIn(displayable_path(item2.path), out)
 
@@ -58,8 +58,8 @@ class InfoTest(PluginTestCase):
         item.store()
 
         out = self.run_with_output("info", "--library", "album:xxxx")
-        self.assertIn(displayable_path(item.path), out)
-        self.assertIn("album: xxxx", out)
+        assert displayable_path(item.path) in out
+        assert "album: xxxx" in out
 
     def test_collect_item_and_path(self):
         path = self.create_mediafile_fixture()
@@ -76,9 +76,9 @@ class InfoTest(PluginTestCase):
         mediafile.save()
 
         out = self.run_with_output("info", "--summarize", "album:AAA", path)
-        self.assertIn("album: AAA", out)
-        self.assertIn("tracktotal: 5", out)
-        self.assertIn("title: [various]", out)
+        assert "album: AAA" in out
+        assert "tracktotal: 5" in out
+        assert "title: [various]" in out
 
     def test_collect_item_and_path_with_multi_values(self):
         path = self.create_mediafile_fixture()
@@ -101,11 +101,11 @@ class InfoTest(PluginTestCase):
         mediafile.save()
 
         out = self.run_with_output("info", "--summarize", "album:AAA", path)
-        self.assertIn("album: AAA", out)
-        self.assertIn("tracktotal: 5", out)
-        self.assertIn("title: [various]", out)
-        self.assertIn("albumartists: [various]", out)
-        self.assertIn("artists: Artist A; Artist Z", out)
+        assert "album: AAA" in out
+        assert "tracktotal: 5" in out
+        assert "title: [various]" in out
+        assert "albumartists: [various]" in out
+        assert "artists: Artist A; Artist Z" in out
 
     def test_custom_format(self):
         self.add_item_fixtures()
diff --git a/test/plugins/test_lyrics.py b/test/plugins/test_lyrics.py
index d756c1846..c636604c5 100644
--- a/test/plugins/test_lyrics.py
+++ b/test/plugins/test_lyrics.py
@@ -45,34 +45,32 @@ class LyricsPluginTest(unittest.TestCase):
 
     def test_search_artist(self):
         item = Item(artist="Alice ft. Bob", title="song")
-        self.assertIn(("Alice ft. Bob", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("Alice", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice ft. Bob", ["song"]) in lyrics.search_pairs(item)
+        assert ("Alice", ["song"]) in lyrics.search_pairs(item)
 
         item = Item(artist="Alice feat Bob", title="song")
-        self.assertIn(("Alice feat Bob", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("Alice", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice feat Bob", ["song"]) in lyrics.search_pairs(item)
+        assert ("Alice", ["song"]) in lyrics.search_pairs(item)
 
         item = Item(artist="Alice feat. Bob", title="song")
-        self.assertIn(("Alice feat. Bob", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("Alice", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice feat. Bob", ["song"]) in lyrics.search_pairs(item)
+        assert ("Alice", ["song"]) in lyrics.search_pairs(item)
 
         item = Item(artist="Alice feats Bob", title="song")
-        self.assertIn(("Alice feats Bob", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice feats Bob", ["song"]) in lyrics.search_pairs(item)
         self.assertNotIn(("Alice", ["song"]), lyrics.search_pairs(item))
 
         item = Item(artist="Alice featuring Bob", title="song")
-        self.assertIn(
-            ("Alice featuring Bob", ["song"]), lyrics.search_pairs(item)
-        )
-        self.assertIn(("Alice", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice featuring Bob", ["song"]) in lyrics.search_pairs(item)
+        assert ("Alice", ["song"]) in lyrics.search_pairs(item)
 
         item = Item(artist="Alice & Bob", title="song")
-        self.assertIn(("Alice & Bob", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("Alice", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice & Bob", ["song"]) in lyrics.search_pairs(item)
+        assert ("Alice", ["song"]) in lyrics.search_pairs(item)
 
         item = Item(artist="Alice and Bob", title="song")
-        self.assertIn(("Alice and Bob", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("Alice", ["song"]), lyrics.search_pairs(item))
+        assert ("Alice and Bob", ["song"]) in lyrics.search_pairs(item)
+        assert ("Alice", ["song"]) in lyrics.search_pairs(item)
 
         item = Item(artist="Alice and Bob", title="song")
         self.assertEqual(
@@ -81,8 +79,8 @@ class LyricsPluginTest(unittest.TestCase):
 
     def test_search_artist_sort(self):
         item = Item(artist="CHVRCHΞS", title="song", artist_sort="CHVRCHES")
-        self.assertIn(("CHVRCHΞS", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("CHVRCHES", ["song"]), lyrics.search_pairs(item))
+        assert ("CHVRCHΞS", ["song"]) in lyrics.search_pairs(item)
+        assert ("CHVRCHES", ["song"]) in lyrics.search_pairs(item)
 
         # Make sure that the original artist name is still the first entry
         self.assertEqual(
@@ -92,8 +90,8 @@ class LyricsPluginTest(unittest.TestCase):
         item = Item(
             artist="横山克", title="song", artist_sort="Masaru Yokoyama"
         )
-        self.assertIn(("横山克", ["song"]), lyrics.search_pairs(item))
-        self.assertIn(("Masaru Yokoyama", ["song"]), lyrics.search_pairs(item))
+        assert ("横山克", ["song"]) in lyrics.search_pairs(item)
+        assert ("Masaru Yokoyama", ["song"]) in lyrics.search_pairs(item)
 
         # Make sure that the original artist name is still the first entry
         self.assertEqual(
@@ -102,41 +100,41 @@ class LyricsPluginTest(unittest.TestCase):
 
     def test_search_pairs_multi_titles(self):
         item = Item(title="1 / 2", artist="A")
-        self.assertIn(("A", ["1 / 2"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["1", "2"]), lyrics.search_pairs(item))
+        assert ("A", ["1 / 2"]) in lyrics.search_pairs(item)
+        assert ("A", ["1", "2"]) in lyrics.search_pairs(item)
 
         item = Item(title="1/2", artist="A")
-        self.assertIn(("A", ["1/2"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["1", "2"]), lyrics.search_pairs(item))
+        assert ("A", ["1/2"]) in lyrics.search_pairs(item)
+        assert ("A", ["1", "2"]) in lyrics.search_pairs(item)
 
     def test_search_pairs_titles(self):
         item = Item(title="Song (live)", artist="A")
-        self.assertIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song (live)"]), lyrics.search_pairs(item))
+        assert ("A", ["Song"]) in lyrics.search_pairs(item)
+        assert ("A", ["Song (live)"]) in lyrics.search_pairs(item)
 
         item = Item(title="Song (live) (new)", artist="A")
-        self.assertIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song (live) (new)"]), lyrics.search_pairs(item))
+        assert ("A", ["Song"]) in lyrics.search_pairs(item)
+        assert ("A", ["Song (live) (new)"]) in lyrics.search_pairs(item)
 
         item = Item(title="Song (live (new))", artist="A")
-        self.assertIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song (live (new))"]), lyrics.search_pairs(item))
+        assert ("A", ["Song"]) in lyrics.search_pairs(item)
+        assert ("A", ["Song (live (new))"]) in lyrics.search_pairs(item)
 
         item = Item(title="Song ft. B", artist="A")
-        self.assertIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song ft. B"]), lyrics.search_pairs(item))
+        assert ("A", ["Song"]) in lyrics.search_pairs(item)
+        assert ("A", ["Song ft. B"]) in lyrics.search_pairs(item)
 
         item = Item(title="Song featuring B", artist="A")
-        self.assertIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song featuring B"]), lyrics.search_pairs(item))
+        assert ("A", ["Song"]) in lyrics.search_pairs(item)
+        assert ("A", ["Song featuring B"]) in lyrics.search_pairs(item)
 
         item = Item(title="Song and B", artist="A")
         self.assertNotIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song and B"]), lyrics.search_pairs(item))
+        assert ("A", ["Song and B"]) in lyrics.search_pairs(item)
 
         item = Item(title="Song: B", artist="A")
-        self.assertIn(("A", ["Song"]), lyrics.search_pairs(item))
-        self.assertIn(("A", ["Song: B"]), lyrics.search_pairs(item))
+        assert ("A", ["Song"]) in lyrics.search_pairs(item)
+        assert ("A", ["Song: B"]) in lyrics.search_pairs(item)
 
     def test_remove_credits(self):
         self.assertEqual(
diff --git a/test/plugins/test_mbsubmit.py b/test/plugins/test_mbsubmit.py
index 01ef522c6..f92d85973 100644
--- a/test/plugins/test_mbsubmit.py
+++ b/test/plugins/test_mbsubmit.py
@@ -51,7 +51,7 @@ class MBSubmitPluginTest(PluginMixin, TerminalImportMixin, ImportTestCase):
             "01. Tag Track 1 - Tag Artist (0:01)\n"
             "02. Tag Track 2 - Tag Artist (0:01)"
         )
-        self.assertIn(tracklist, output.getvalue())
+        assert tracklist in output.getvalue()
 
     def test_print_tracks_output_as_tracks(self):
         """Test the output of the "print tracks" choice, as singletons."""
@@ -66,4 +66,4 @@ class MBSubmitPluginTest(PluginMixin, TerminalImportMixin, ImportTestCase):
         tracklist = (
             "Open files with Picard? " "02. Tag Track 2 - Tag Artist (0:01)"
         )
-        self.assertIn(tracklist, output.getvalue())
+        assert tracklist in output.getvalue()
diff --git a/test/plugins/test_mbsync.py b/test/plugins/test_mbsync.py
index 759a4a2b4..365d0140f 100644
--- a/test/plugins/test_mbsync.py
+++ b/test/plugins/test_mbsync.py
@@ -57,8 +57,8 @@ class MbsyncCliTest(PluginTestCase):
         with capture_log() as logs:
             self.run_command("mbsync")
 
-        self.assertIn("Sending event: albuminfo_received", logs)
-        self.assertIn("Sending event: trackinfo_received", logs)
+        assert "Sending event: albuminfo_received" in logs
+        assert "Sending event: trackinfo_received" in logs
 
         item.load()
         self.assertEqual(item.title, "singleton info")
diff --git a/test/plugins/test_mpdstats.py b/test/plugins/test_mpdstats.py
index a3bf14242..539e7cef2 100644
--- a/test/plugins/test_mpdstats.py
+++ b/test/plugins/test_mpdstats.py
@@ -44,7 +44,7 @@ class MPDStatsTest(PluginTestCase):
 
         self.assertEqual(str(mpdstats.get_item(item_path)), str(item))
         assert mpdstats.get_item("/some/non-existing/path") is None
-        self.assertIn("item not found:", log.info.call_args[0][0])
+        assert "item not found:" in log.info.call_args[0][0]
 
     FAKE_UNKNOWN_STATE = "some-unknown-one"
     STATUSES = [
diff --git a/test/plugins/test_player.py b/test/plugins/test_player.py
index bc1e9a1f3..95bf699c6 100644
--- a/test/plugins/test_player.py
+++ b/test/plugins/test_player.py
@@ -1034,7 +1034,7 @@ class BPDDatabaseTest(BPDTestHelper):
                 "lsinfo", response2.data["directory"]
             )
             self._assert_ok(response3)
-        self.assertIn(self.item1.title, response3.data["Title"])
+        assert self.item1.title in response3.data["Title"]
 
     def test_cmd_count(self):
         with self.run_bpd() as client:
diff --git a/test/plugins/test_plugin_mediafield.py b/test/plugins/test_plugin_mediafield.py
index 1275df353..b9789e526 100644
--- a/test/plugins/test_plugin_mediafield.py
+++ b/test/plugins/test_plugin_mediafield.py
@@ -117,9 +117,9 @@ class ExtendedFieldTestMixin(BeetsTestCase):
     def test_invalid_descriptor(self):
         with self.assertRaises(ValueError) as cm:
             mediafile.MediaFile.add_field("somekey", True)
-        self.assertIn("must be an instance of MediaField", str(cm.exception))
+        assert "must be an instance of MediaField" in str(cm.exception)
 
     def test_overwrite_property(self):
         with self.assertRaises(ValueError) as cm:
             mediafile.MediaFile.add_field("artist", mediafile.MediaField())
-        self.assertIn('property "artist" already exists', str(cm.exception))
+        assert 'property "artist" already exists' in str(cm.exception)
diff --git a/test/plugins/test_spotify.py b/test/plugins/test_spotify.py
index 3fed3f914..b465916ba 100644
--- a/test/plugins/test_spotify.py
+++ b/test/plugins/test_spotify.py
@@ -79,9 +79,9 @@ class SpotifyPluginTest(BeetsTestCase):
 
         params = _params(responses.calls[0].request.url)
         query = params["q"][0]
-        self.assertIn("duifhjslkef", query)
-        self.assertIn("artist:ujydfsuihse", query)
-        self.assertIn("album:lkajsdflakjsd", query)
+        assert "duifhjslkef" in query
+        assert "artist:ujydfsuihse" in query
+        assert "album:lkajsdflakjsd" in query
         self.assertEqual(params["type"], ["track"])
 
     @responses.activate
@@ -114,9 +114,9 @@ class SpotifyPluginTest(BeetsTestCase):
 
         params = _params(responses.calls[0].request.url)
         query = params["q"][0]
-        self.assertIn("Happy", query)
-        self.assertIn("artist:Pharrell Williams", query)
-        self.assertIn("album:Despicable Me 2", query)
+        assert "Happy" in query
+        assert "artist:Pharrell Williams" in query
+        assert "album:Despicable Me 2" in query
         self.assertEqual(params["type"], ["track"])
 
     @responses.activate
diff --git a/test/plugins/test_types_plugin.py b/test/plugins/test_types_plugin.py
index 3f6bb5b70..d841b00a8 100644
--- a/test/plugins/test_types_plugin.py
+++ b/test/plugins/test_types_plugin.py
@@ -38,7 +38,7 @@ class TypesPluginTest(PluginTestCase):
 
         # Match in range
         out = self.list("myint:1..3")
-        self.assertIn("aaa", out)
+        assert "aaa" in out
 
     def test_album_integer_modify_and_query(self):
         self.config["types"] = {"myint": "int"}
@@ -54,7 +54,7 @@ class TypesPluginTest(PluginTestCase):
 
         # Match in range
         out = self.list_album("myint:1..3")
-        self.assertIn("aaa", out)
+        assert "aaa" in out
 
     def test_float_modify_and_query(self):
         self.config["types"] = {"myfloat": "float"}
@@ -70,7 +70,7 @@ class TypesPluginTest(PluginTestCase):
 
         # Match in range
         out = self.list("myfloat:-10..0")
-        self.assertIn("aaa", out)
+        assert "aaa" in out
 
     def test_bool_modify_and_query(self):
         self.config["types"] = {"mybool": "bool"}
@@ -101,7 +101,7 @@ class TypesPluginTest(PluginTestCase):
         # Dealing with unset fields?
         # self.assertEqual('false False', out)
         # out = self.list('mybool:', '$artist $mybool')
-        # self.assertIn('unset $mybool', out)
+        # assert 'unset $mybool' in out
 
     def test_date_modify_and_query(self):
         self.config["types"] = {"mydate": "date"}
@@ -170,9 +170,10 @@ class TypesPluginTest(PluginTestCase):
         )
 
         bool_template = "%ifdef{starred,Starred: $starred,Not starred}"
-        self.assertIn(
-            with_fields.evaluate_template(bool_template).lower(),
-            ("starred: true", "starred: yes", "starred: y"),
+        assert with_fields.evaluate_template(bool_template).lower() in (
+            "starred: true",
+            "starred: yes",
+            "starred: y",
         )
         self.assertEqual(
             without_fields.evaluate_template(bool_template), "Not starred"
diff --git a/test/test_autotag.py b/test/test_autotag.py
index 6928f42e2..51ea09bc2 100644
--- a/test/test_autotag.py
+++ b/test/test_autotag.py
@@ -42,7 +42,7 @@ class PluralityTest(BeetsTestCase):
     def test_plurality_conflict(self):
         objs = [1, 1, 2, 2, 3]
         obj, freq = plurality(objs)
-        self.assertIn(obj, (1, 2))
+        assert obj in (1, 2)
         self.assertEqual(freq, 2)
 
     def test_plurality_empty_sequence_raises_error(self):
diff --git a/test/test_config_command.py b/test/test_config_command.py
index 6f94bf872..5d3a4c796 100644
--- a/test/test_config_command.py
+++ b/test/test_config_command.py
@@ -114,8 +114,8 @@ class ConfigCommandTest(BeetsTestCase):
             with patch("os.execlp") as execlp:
                 execlp.side_effect = OSError("here is problem")
                 self.run_command("config", "-e")
-        self.assertIn("Could not edit configuration", str(user_error.exception))
-        self.assertIn("here is problem", str(user_error.exception))
+        assert "Could not edit configuration" in str(user_error.exception)
+        assert "here is problem" in str(user_error.exception)
 
     def test_edit_invalid_config_file(self):
         with open(self.config_path, "w") as file:
diff --git a/test/test_dbcore.py b/test/test_dbcore.py
index 732bc5e41..6e776f58b 100644
--- a/test/test_dbcore.py
+++ b/test/test_dbcore.py
@@ -314,14 +314,14 @@ class ModelTest(unittest.TestCase):
     def test_delete_flexattr(self):
         model = ModelFixture1()
         model["foo"] = "bar"
-        self.assertIn("foo", model)
+        assert "foo" in model
         del model["foo"]
         self.assertNotIn("foo", model)
 
     def test_delete_flexattr_via_dot(self):
         model = ModelFixture1()
         model["foo"] = "bar"
-        self.assertIn("foo", model)
+        assert "foo" in model
         del model.foo
         self.assertNotIn("foo", model)
 
@@ -377,7 +377,7 @@ class ModelTest(unittest.TestCase):
         model1.add(self.db)
 
         model2 = self.db._get(ModelFixture1, model1.id)
-        self.assertIn("flex_field", model2)
+        assert "flex_field" in model2
 
         del model1["flex_field"]
         model1.store()
diff --git a/test/test_files.py b/test/test_files.py
index 64833e6a5..3844f4c76 100644
--- a/test/test_files.py
+++ b/test/test_files.py
@@ -124,20 +124,20 @@ class MoveTest(BeetsTestCase):
     def test_move_file_with_colon(self):
         self.i.artist = "C:DOS"
         self.i.move()
-        self.assertIn("C_DOS", self.i.path.decode())
+        assert "C_DOS" in self.i.path.decode()
 
     def test_move_file_with_multiple_colons(self):
         # print(beets.config["replace"])
         self.i.artist = "COM:DOS"
         self.i.move()
-        self.assertIn("COM_DOS", self.i.path.decode())
+        assert "COM_DOS" in self.i.path.decode()
 
     def test_move_file_with_colon_alt_separator(self):
         old = beets.config["drive_sep_replace"]
         beets.config["drive_sep_replace"] = "0"
         self.i.artist = "C:DOS"
         self.i.move()
-        self.assertIn("C0DOS", self.i.path.decode())
+        assert "C0DOS" in self.i.path.decode()
         beets.config["drive_sep_replace"] = old
 
     def test_read_only_file_copied_writable(self):
@@ -302,7 +302,7 @@ class AlbumFileTest(BeetsTestCase):
         self.ai.move(basedir=self.otherdir)
         self.i.load()
         self.ai.store()
-        self.assertIn(b"testotherdir", self.i.path)
+        assert b"testotherdir" in self.i.path
 
 
 class ArtFileTest(BeetsTestCase):
@@ -352,7 +352,7 @@ class ArtFileTest(BeetsTestCase):
         self.assertNotExists(self.art)
         newart = self.lib.get_album(self.i).artpath
         self.assertExists(newart)
-        self.assertIn(b"testotherdir", newart)
+        assert b"testotherdir" in newart
 
     def test_setart_copies_image(self):
         util.remove(self.art)
diff --git a/test/test_importer.py b/test/test_importer.py
index 166a62768..d7ccc3f01 100644
--- a/test/test_importer.py
+++ b/test/test_importer.py
@@ -556,7 +556,7 @@ class ImportTest(ImportTestCase):
             self.importer.run()
 
         import_dir = displayable_path(import_dir)
-        self.assertIn(f"No files imported from {import_dir}", logs)
+        assert f"No files imported from {import_dir}" in logs
 
     def test_empty_directory_singleton_warning(self):
         import_dir = os.path.join(self.temp_dir, b"empty")
@@ -566,7 +566,7 @@ class ImportTest(ImportTestCase):
             self.importer.run()
 
         import_dir = displayable_path(import_dir)
-        self.assertIn(f"No files imported from {import_dir}", logs)
+        assert f"No files imported from {import_dir}" in logs
 
     def test_asis_no_data_source(self):
         assert self.lib.items().get() is None
@@ -1317,14 +1317,14 @@ class TagLogTest(BeetsTestCase):
         handler = logging.StreamHandler(sio)
         session = _common.import_session(loghandler=handler)
         session.tag_log("status", "path")
-        self.assertIn("status path", sio.getvalue())
+        assert "status path" in sio.getvalue()
 
     def test_tag_log_unicode(self):
         sio = StringIO()
         handler = logging.StreamHandler(sio)
         session = _common.import_session(loghandler=handler)
         session.tag_log("status", "caf\xe9")  # send unicode
-        self.assertIn("status caf\xe9", sio.getvalue())
+        assert "status caf\xe9" in sio.getvalue()
 
 
 class ResumeImportTest(ImportTestCase):
@@ -1440,10 +1440,10 @@ class AlbumsInDirTest(BeetsTestCase):
         found = []
         for _, album in albums_in_dir(self.base):
             found.append(re.search(rb"album(.)song", album[0]).group(1))
-        self.assertIn(b"1", found)
-        self.assertIn(b"2", found)
-        self.assertIn(b"3", found)
-        self.assertIn(b"4", found)
+        assert b"1" in found
+        assert b"2" in found
+        assert b"3" in found
+        assert b"4" in found
 
     def test_finds_multiple_songs(self):
         for _, album in albums_in_dir(self.base):
diff --git a/test/test_library.py b/test/test_library.py
index b4421e89b..c406eb113 100644
--- a/test/test_library.py
+++ b/test/test_library.py
@@ -48,7 +48,7 @@ class LoadTest(ItemInDBTestCase):
 
     def test_load_clears_dirty_flags(self):
         self.i.artist = "something"
-        self.assertIn("artist", self.i._dirty)
+        assert "artist" in self.i._dirty
         self.i.load()
         self.assertNotIn("artist", self.i._dirty)
 
@@ -143,7 +143,7 @@ class GetSetTest(BeetsTestCase):
 
     def test_set_sets_dirty_flag(self):
         self.i.comp = not self.i.comp
-        self.assertIn("comp", self.i._dirty)
+        assert "comp" in self.i._dirty
 
     def test_set_does_not_dirty_if_value_unchanged(self):
         self.i.title = self.i.title
@@ -159,7 +159,7 @@ class GetSetTest(BeetsTestCase):
         album["flex"] = "foo"
         album.store()
 
-        self.assertIn("flex", i)
+        assert "flex" in i
         self.assertNotIn("flex", i.keys(with_album=False))
         self.assertEqual(i["flex"], "foo")
         self.assertEqual(i.get("flex"), "foo")
@@ -231,21 +231,21 @@ class DestinationTest(BeetsTestCase):
     def test_destination_escapes_slashes(self):
         self.i.album = "one/two"
         dest = self.i.destination()
-        self.assertIn(b"one", dest)
-        self.assertIn(b"two", dest)
+        assert b"one" in dest
+        assert b"two" in dest
         self.assertNotIn(b"one/two", dest)
 
     def test_destination_escapes_leading_dot(self):
         self.i.album = ".something"
         dest = self.i.destination()
-        self.assertIn(b"something", dest)
+        assert b"something" in dest
         self.assertNotIn(b"/.something", dest)
 
     def test_destination_preserves_legitimate_slashes(self):
         self.i.artist = "one"
         self.i.album = "two"
         dest = self.i.destination()
-        self.assertIn(os.path.join(b"one", b"two"), dest)
+        assert os.path.join(b"one", b"two") in dest
 
     def test_destination_long_names_truncated(self):
         self.i.title = "X" * 300
@@ -271,7 +271,7 @@ class DestinationTest(BeetsTestCase):
     def test_path_with_format(self):
         self.lib.path_formats = [("default", "$artist/$album ($format)")]
         p = self.i.destination()
-        self.assertIn(b"(FLAC)", p)
+        assert b"(FLAC)" in p
 
     def test_heterogeneous_album_gets_single_directory(self):
         i1, i2 = item(), item()
@@ -429,7 +429,7 @@ class DestinationTest(BeetsTestCase):
             p = self.i.destination()
             self.assertNotIn(b"?", p)
             # We use UTF-8 to encode Windows paths now.
-            self.assertIn("h\u0259d".encode(), p)
+            assert "h\u0259d".encode() in p
         finally:
             sys.getfilesystemencoding = oldfunc
 
@@ -1052,7 +1052,7 @@ class ArtDestinationTest(BeetsTestCase):
     def test_art_filename_respects_setting(self):
         art = self.ai.art_destination("something.jpg")
         new_art = bytestring_path("%sartimage.jpg" % os.path.sep)
-        self.assertIn(new_art, art)
+        assert new_art in art
 
     def test_art_path_in_item_dir(self):
         art = self.ai.art_destination("something.jpg")
@@ -1062,7 +1062,7 @@ class ArtDestinationTest(BeetsTestCase):
     def test_art_path_sanitized(self):
         config["art_filename"] = "artXimage"
         art = self.ai.art_destination("something.jpg")
-        self.assertIn(b"artYimage", art)
+        assert b"artYimage" in art
 
 
 class PathStringTest(BeetsTestCase):
diff --git a/test/test_logging.py b/test/test_logging.py
index 0c84bbe73..1608897d0 100644
--- a/test/test_logging.py
+++ b/test/test_logging.py
@@ -86,31 +86,31 @@ class LoggingLevelTest(AsIsImporterMixin, PluginMixin, ImportTestCase):
         self.config["verbose"] = 0
         with helper.capture_log() as logs:
             self.run_command("dummy")
-        self.assertIn("dummy: warning cmd", logs)
-        self.assertIn("dummy: info cmd", logs)
+        assert "dummy: warning cmd" in logs
+        assert "dummy: info cmd" in logs
         self.assertNotIn("dummy: debug cmd", logs)
 
     def test_command_level1(self):
         self.config["verbose"] = 1
         with helper.capture_log() as logs:
             self.run_command("dummy")
-        self.assertIn("dummy: warning cmd", logs)
-        self.assertIn("dummy: info cmd", logs)
-        self.assertIn("dummy: debug cmd", logs)
+        assert "dummy: warning cmd" in logs
+        assert "dummy: info cmd" in logs
+        assert "dummy: debug cmd" in logs
 
     def test_command_level2(self):
         self.config["verbose"] = 2
         with helper.capture_log() as logs:
             self.run_command("dummy")
-        self.assertIn("dummy: warning cmd", logs)
-        self.assertIn("dummy: info cmd", logs)
-        self.assertIn("dummy: debug cmd", logs)
+        assert "dummy: warning cmd" in logs
+        assert "dummy: info cmd" in logs
+        assert "dummy: debug cmd" in logs
 
     def test_listener_level0(self):
         self.config["verbose"] = 0
         with helper.capture_log() as logs:
             plugins.send("dummy_event")
-        self.assertIn("dummy: warning listener", logs)
+        assert "dummy: warning listener" in logs
         self.assertNotIn("dummy: info listener", logs)
         self.assertNotIn("dummy: debug listener", logs)
 
@@ -118,23 +118,23 @@ class LoggingLevelTest(AsIsImporterMixin, PluginMixin, ImportTestCase):
         self.config["verbose"] = 1
         with helper.capture_log() as logs:
             plugins.send("dummy_event")
-        self.assertIn("dummy: warning listener", logs)
-        self.assertIn("dummy: info listener", logs)
+        assert "dummy: warning listener" in logs
+        assert "dummy: info listener" in logs
         self.assertNotIn("dummy: debug listener", logs)
 
     def test_listener_level2(self):
         self.config["verbose"] = 2
         with helper.capture_log() as logs:
             plugins.send("dummy_event")
-        self.assertIn("dummy: warning listener", logs)
-        self.assertIn("dummy: info listener", logs)
-        self.assertIn("dummy: debug listener", logs)
+        assert "dummy: warning listener" in logs
+        assert "dummy: info listener" in logs
+        assert "dummy: debug listener" in logs
 
     def test_import_stage_level0(self):
         self.config["verbose"] = 0
         with helper.capture_log() as logs:
             self.run_asis_importer()
-        self.assertIn("dummy: warning import_stage", logs)
+        assert "dummy: warning import_stage" in logs
         self.assertNotIn("dummy: info import_stage", logs)
         self.assertNotIn("dummy: debug import_stage", logs)
 
@@ -142,17 +142,17 @@ class LoggingLevelTest(AsIsImporterMixin, PluginMixin, ImportTestCase):
         self.config["verbose"] = 1
         with helper.capture_log() as logs:
             self.run_asis_importer()
-        self.assertIn("dummy: warning import_stage", logs)
-        self.assertIn("dummy: info import_stage", logs)
+        assert "dummy: warning import_stage" in logs
+        assert "dummy: info import_stage" in logs
         self.assertNotIn("dummy: debug import_stage", logs)
 
     def test_import_stage_level2(self):
         self.config["verbose"] = 2
         with helper.capture_log() as logs:
             self.run_asis_importer()
-        self.assertIn("dummy: warning import_stage", logs)
-        self.assertIn("dummy: info import_stage", logs)
-        self.assertIn("dummy: debug import_stage", logs)
+        assert "dummy: warning import_stage" in logs
+        assert "dummy: info import_stage" in logs
+        assert "dummy: debug import_stage" in logs
 
 
 @_common.slow_test()
@@ -266,10 +266,10 @@ class ConcurrentEventsTest(AsIsImporterMixin, ImportTestCase):
         with helper.capture_log() as logs:
             self.run_asis_importer()
         for l in logs:
-            self.assertIn("import", l)
-            self.assertIn("album", l)
+            assert "import" in l
+            assert "album" in l
 
         blog.getLogger("beets").set_global_level(blog.DEBUG)
         with helper.capture_log() as logs:
             self.run_asis_importer()
-        self.assertIn("Sending event: database_change", logs)
+        assert "Sending event: database_change" in logs
diff --git a/test/test_metasync.py b/test/test_metasync.py
index f3b9c4912..00a881a35 100644
--- a/test/test_metasync.py
+++ b/test/test_metasync.py
@@ -84,19 +84,19 @@ class MetaSyncTest(PluginTestCase):
 
     def test_load_item_types(self):
         # This test also verifies that the MetaSources have loaded correctly
-        self.assertIn("amarok_score", Item._types)
-        self.assertIn("itunes_rating", Item._types)
+        assert "amarok_score" in Item._types
+        assert "itunes_rating" in Item._types
 
     def test_pretend_sync_from_itunes(self):
         out = self.run_with_output("metasync", "-p")
 
-        self.assertIn("itunes_rating: 60 -> 80", out)
-        self.assertIn("itunes_rating: 100", out)
-        self.assertIn("itunes_playcount: 31", out)
-        self.assertIn("itunes_skipcount: 3", out)
-        self.assertIn("itunes_lastplayed: 2015-05-04 12:20:51", out)
-        self.assertIn("itunes_lastskipped: 2015-02-05 15:41:04", out)
-        self.assertIn("itunes_dateadded: 2014-04-24 09:28:38", out)
+        assert "itunes_rating: 60 -> 80" in out
+        assert "itunes_rating: 100" in out
+        assert "itunes_playcount: 31" in out
+        assert "itunes_skipcount: 3" in out
+        assert "itunes_lastplayed: 2015-05-04 12:20:51" in out
+        assert "itunes_lastskipped: 2015-02-05 15:41:04" in out
+        assert "itunes_dateadded: 2014-04-24 09:28:38" in out
         self.assertEqual(self.lib.items()[0].itunes_rating, 60)
 
     def test_sync_from_itunes(self):
diff --git a/test/test_plugins.py b/test/test_plugins.py
index 02dd910e6..a44700534 100644
--- a/test/test_plugins.py
+++ b/test/test_plugins.py
@@ -95,7 +95,7 @@ class ItemTypesTest(PluginLoaderTestCase):
 
         # Match in range
         out = self.run_with_output("ls", "rating:1..3")
-        self.assertIn("aaa", out)
+        assert "aaa" in out
 
         # Don't match out of range
         out = self.run_with_output("ls", "rating:3..5")
diff --git a/test/test_query.py b/test/test_query.py
index 9cbc626f9..7e8436a87 100644
--- a/test/test_query.py
+++ b/test/test_query.py
@@ -48,7 +48,7 @@ class AssertsMixin:
 
     def assertInResult(self, item, results):  # noqa
         result_ids = [i.id for i in results]
-        self.assertIn(item.id, result_ids)
+        assert item.id in result_ids
 
     def assertNotInResult(self, item, results):  # noqa
         result_ids = [i.id for i in results]
@@ -406,13 +406,13 @@ class GetTest(DummyDataTestCase):
     def test_invalid_query(self):
         with self.assertRaises(InvalidQueryArgumentValueError) as raised:
             dbcore.query.NumericQuery("year", "199a")
-        self.assertIn("not an int", str(raised.exception))
+        assert "not an int" in str(raised.exception)
 
         with self.assertRaises(InvalidQueryArgumentValueError) as raised:
             dbcore.query.RegexpQuery("year", "199(")
         exception_text = str(raised.exception)
-        self.assertIn("not a regular expression", exception_text)
-        self.assertIn("unterminated subpattern", exception_text)
+        assert "not a regular expression" in exception_text
+        assert "unterminated subpattern" in exception_text
         self.assertIsInstance(raised.exception, ParsingError)
 
 
diff --git a/test/test_ui.py b/test/test_ui.py
index 0b8e107e0..6e50e6216 100644
--- a/test/test_ui.py
+++ b/test/test_ui.py
@@ -56,7 +56,7 @@ class ListTest(BeetsTestCase):
 
     def test_list_outputs_item(self):
         stdout = self._run_list()
-        self.assertIn("the title", stdout.getvalue())
+        assert "the title" in stdout.getvalue()
 
     def test_list_unicode_query(self):
         self.item.title = "na\xefve"
@@ -65,7 +65,7 @@ class ListTest(BeetsTestCase):
 
         stdout = self._run_list(["na\xefve"])
         out = stdout.getvalue()
-        self.assertIn("na\xefve", out)
+        assert "na\xefve" in out
 
     def test_list_item_path(self):
         stdout = self._run_list(fmt="$path")
@@ -85,17 +85,17 @@ class ListTest(BeetsTestCase):
 
     def test_list_uses_track_artist(self):
         stdout = self._run_list()
-        self.assertIn("the artist", stdout.getvalue())
+        assert "the artist" in stdout.getvalue()
         self.assertNotIn("the album artist", stdout.getvalue())
 
     def test_list_album_uses_album_artist(self):
         stdout = self._run_list(album=True)
         self.assertNotIn("the artist", stdout.getvalue())
-        self.assertIn("the album artist", stdout.getvalue())
+        assert "the album artist" in stdout.getvalue()
 
     def test_list_item_format_artist(self):
         stdout = self._run_list(fmt="$artist")
-        self.assertIn("the artist", stdout.getvalue())
+        assert "the artist" in stdout.getvalue()
 
     def test_list_item_format_multiple(self):
         stdout = self._run_list(fmt="$artist - $album - $year")
@@ -105,7 +105,7 @@ class ListTest(BeetsTestCase):
 
     def test_list_album_format(self):
         stdout = self._run_list(album=True, fmt="$genre")
-        self.assertIn("the genre", stdout.getvalue())
+        assert "the genre" in stdout.getvalue()
         self.assertNotIn("the album", stdout.getvalue())
 
 
@@ -235,7 +235,7 @@ class ModifyTest(BeetsTestCase):
     def test_move(self):
         self.modify("title=newTitle")
         item = self.lib.items().get()
-        self.assertIn(b"newTitle", item.path)
+        assert b"newTitle" in item.path
 
     def test_not_move(self):
         self.modify("--nomove", "title=newTitle")
@@ -317,7 +317,7 @@ class ModifyTest(BeetsTestCase):
         self.modify("--album", "album=newAlbum")
         item = self.lib.items().get()
         item.read()
-        self.assertIn(b"newAlbum", item.path)
+        assert b"newAlbum" in item.path
 
     def test_album_not_move(self):
         self.modify("--nomove", "--album", "album=newAlbum")
@@ -439,7 +439,7 @@ class WriteTest(BeetsTestCase):
 
         output = self.write_cmd()
 
-        self.assertIn(f"{old_title} -> new title", output)
+        assert f"{old_title} -> new title" in output
 
 
 class MoveTest(BeetsTestCase):
@@ -478,54 +478,54 @@ class MoveTest(BeetsTestCase):
     def test_move_item(self):
         self._move()
         self.i.load()
-        self.assertIn(b"libdir", self.i.path)
+        assert b"libdir" in self.i.path
         self.assertExists(self.i.path)
         self.assertNotExists(self.itempath)
 
     def test_copy_item(self):
         self._move(copy=True)
         self.i.load()
-        self.assertIn(b"libdir", self.i.path)
+        assert b"libdir" in self.i.path
         self.assertExists(self.i.path)
         self.assertExists(self.itempath)
 
     def test_move_album(self):
         self._move(album=True)
         self.i.load()
-        self.assertIn(b"libdir", self.i.path)
+        assert b"libdir" in self.i.path
         self.assertExists(self.i.path)
         self.assertNotExists(self.itempath)
 
     def test_copy_album(self):
         self._move(copy=True, album=True)
         self.i.load()
-        self.assertIn(b"libdir", self.i.path)
+        assert b"libdir" in self.i.path
         self.assertExists(self.i.path)
         self.assertExists(self.itempath)
 
     def test_move_item_custom_dir(self):
         self._move(dest=self.otherdir)
         self.i.load()
-        self.assertIn(b"testotherdir", self.i.path)
+        assert b"testotherdir" in self.i.path
         self.assertExists(self.i.path)
         self.assertNotExists(self.itempath)
 
     def test_move_album_custom_dir(self):
         self._move(dest=self.otherdir, album=True)
         self.i.load()
-        self.assertIn(b"testotherdir", self.i.path)
+        assert b"testotherdir" in self.i.path
         self.assertExists(self.i.path)
         self.assertNotExists(self.itempath)
 
     def test_pretend_move_item(self):
         self._move(dest=self.otherdir, pretend=True)
         self.i.load()
-        self.assertIn(b"srcfile", self.i.path)
+        assert b"srcfile" in self.i.path
 
     def test_pretend_move_album(self):
         self._move(album=True, pretend=True)
         self.i.load()
-        self.assertIn(b"srcfile", self.i.path)
+        assert b"srcfile" in self.i.path
 
     def test_export_item_custom_dir(self):
         self._move(dest=self.otherdir, export=True)
@@ -542,7 +542,7 @@ class MoveTest(BeetsTestCase):
     def test_pretend_export_item(self):
         self._move(dest=self.otherdir, pretend=True, export=True)
         self.i.load()
-        self.assertIn(b"srcfile", self.i.path)
+        assert b"srcfile" in self.i.path
         self.assertNotExists(self.otherdir)
 
 
@@ -629,7 +629,7 @@ class UpdateTest(BeetsTestCase):
         mf.save()
         self._update(move=True)
         item = self.lib.items().get()
-        self.assertIn(b"differentTitle", item.path)
+        assert b"differentTitle" in item.path
 
     def test_modified_metadata_not_moved(self):
         mf = MediaFile(syspath(self.i.path))
@@ -646,7 +646,7 @@ class UpdateTest(BeetsTestCase):
         mf.save()
         self._update(move=True, fields=["title"])
         item = self.lib.items().get()
-        self.assertIn(b"differentTitle", item.path)
+        assert b"differentTitle" in item.path
         self.assertNotEqual(item.genre, "differentGenre")
 
     def test_selective_modified_metadata_not_moved(self):
@@ -665,7 +665,7 @@ class UpdateTest(BeetsTestCase):
         mf.save()
         self._update(move=True)
         item = self.lib.items().get()
-        self.assertIn(b"differentAlbum", item.path)
+        assert b"differentAlbum" in item.path
 
     def test_modified_album_metadata_art_moved(self):
         artpath = self.album.artpath
@@ -684,7 +684,7 @@ class UpdateTest(BeetsTestCase):
         mf.save()
         self._update(move=True, fields=["album"])
         item = self.lib.items().get()
-        self.assertIn(b"differentAlbum", item.path)
+        assert b"differentAlbum" in item.path
         self.assertNotEqual(item.genre, "differentGenre")
 
     def test_selective_modified_album_metadata_not_moved(self):
@@ -1152,13 +1152,13 @@ class ShowModelChangeTest(BeetsTestCase):
         self.b.title = "x"
         change, out = self._show()
         assert change
-        self.assertIn("title", out)
+        assert "title" in out
 
     def test_int_fixed_field_change(self):
         self.b.track = 9
         change, out = self._show()
         assert change
-        self.assertIn("track", out)
+        assert "track" in out
 
     def test_floats_close_to_identical(self):
         self.a.length = 1.00001
@@ -1172,14 +1172,14 @@ class ShowModelChangeTest(BeetsTestCase):
         self.b.length = 2.00001
         change, out = self._show()
         assert change
-        self.assertIn("length", out)
+        assert "length" in out
 
     def test_both_values_shown(self):
         self.a.title = "foo"
         self.b.title = "bar"
         change, out = self._show()
-        self.assertIn("foo", out)
-        self.assertIn("bar", out)
+        assert "foo" in out
+        assert "bar" in out
 
 
 class ShowChangeTest(BeetsTestCase):
@@ -1228,15 +1228,15 @@ class ShowChangeTest(BeetsTestCase):
 
     def test_null_change(self):
         msg = self._show_change()
-        self.assertIn("match (90.0%)", msg)
-        self.assertIn("album, artist", msg)
+        assert "match (90.0%)" in msg
+        assert "album in artist", msg
 
     def test_album_data_change(self):
         msg = self._show_change(
             cur_artist="another artist", cur_album="another album"
         )
-        self.assertIn("another artist -> the artist", msg)
-        self.assertIn("another album -> the album", msg)
+        assert "another artist -> the artist" in msg
+        assert "another album -> the album" in msg
 
     def test_item_data_change(self):
         self.items[0].title = "different"
@@ -1317,8 +1317,8 @@ class ShowChangeTest(BeetsTestCase):
                 cur_artist=long_name, cur_album="another album"
             )
             # _common.log.info("Message:{}".format(msg))
-            self.assertIn("artist: another artist", msg)
-            self.assertIn("  -> the artist", msg)
+            assert "artist: another artist" in msg
+            assert "  -> the artist" in msg
             self.assertNotIn("another album -> the album", msg)
 
     def test_item_data_change_wrap_column(self):
@@ -1329,7 +1329,7 @@ class ShowChangeTest(BeetsTestCase):
             long_title = "a track with a" + (" very" * 10) + " long name"
             self.items[0].title = long_title
             msg = self._show_change()
-            self.assertIn("(#1) a track (1:00) -> (#1) the title (0:00)", msg)
+            assert "(#1) a track (1:00) -> (#1) the title (0:00)" in msg
 
     def test_item_data_change_wrap_newline(self):
         # Patch ui.term_width to force wrapping
@@ -1338,8 +1338,8 @@ class ShowChangeTest(BeetsTestCase):
             long_title = "a track with a" + (" very" * 10) + " long name"
             self.items[0].title = long_title
             msg = self._show_change()
-            self.assertIn("(#1) a track with", msg)
-            self.assertIn("     -> (#1) the title (0:00)", msg)
+            assert "(#1) a track with" in msg
+            assert "     -> (#1) the title (0:00)" in msg
 
 
 @patch("beets.library.Item.try_filesize", Mock(return_value=987))
@@ -1499,30 +1499,30 @@ class CommonOptionsParserCliTest(BeetsTestCase):
 
     def test_help(self):
         l = self.run_with_output("help")
-        self.assertIn("Usage:", l)
+        assert "Usage:" in l
 
         l = self.run_with_output("help", "list")
-        self.assertIn("Usage:", l)
+        assert "Usage:" in l
 
         with self.assertRaises(ui.UserError):
             self.run_command("help", "this.is.not.a.real.command")
 
     def test_stats(self):
         l = self.run_with_output("stats")
-        self.assertIn("Approximate total size:", l)
+        assert "Approximate total size:" in l
 
         # # Need to have more realistic library setup for this to work
         # l = self.run_with_output('stats', '-e')
-        # self.assertIn('Total size:', l)
+        # assert 'Total size:' in l
 
     def test_version(self):
         l = self.run_with_output("version")
-        self.assertIn("Python version", l)
-        self.assertIn("no plugins loaded", l)
+        assert "Python version" in l
+        assert "no plugins loaded" in l
 
         # # Need to have plugin loaded
         # l = self.run_with_output('version')
-        # self.assertIn('plugins: ', l)
+        # assert 'plugins: ' in l
 
 
 class CommonOptionsParserTest(BeetsTestCase):