diff --git a/test/plugins/test_replaygain.py b/test/plugins/test_replaygain.py
index 92e3e5f65..d8082b0af 100644
--- a/test/plugins/test_replaygain.py
+++ b/test/plugins/test_replaygain.py
@@ -14,11 +14,12 @@
 
 
 import unittest
+from typing import ClassVar
 
 from mediafile import MediaFile
 
 from beets import config
-from beets.test.helper import TestHelper, has_program
+from beets.test.helper import BeetsTestCase, has_program
 from beetsplug.replaygain import (
     FatalGstreamerPluginReplayGainError,
     GStreamerBackend,
@@ -51,6 +52,34 @@ def reset_replaygain(item):
     item.store()
 
 
+class ReplayGainTestCase(BeetsTestCase):
+    backend: ClassVar[str]
+
+    def setUp(self):
+        # Implemented by Mixins, see above. This may decide to skip the test.
+        self.test_backend()
+
+        self.setup_beets(disk=True)
+        self.config["replaygain"]["backend"] = self.backend
+
+        try:
+            self.load_plugins("replaygain")
+        except Exception:
+            self.tearDown()
+
+        self.importer = self.create_importer()
+
+    def tearDown(self):
+        self.unload_plugins()
+        super().tearDown()
+
+
+class ThreadedImportMixin:
+    def setUp(self):
+        super().setUp()
+        self.config["threaded"] = True
+
+
 class GstBackendMixin:
     backend = "gstreamer"
     has_r128_support = True
@@ -85,22 +114,9 @@ class FfmpegBackendMixin:
         pass
 
 
-class ReplayGainCliTestBase(TestHelper):
+class ReplayGainCliTest:
     FNAME: str
 
-    def setUp(self):
-        # Implemented by Mixins, see above. This may decide to skip the test.
-        self.test_backend()
-
-        self.setup_beets(disk=True)
-        self.config["replaygain"]["backend"] = self.backend
-
-        try:
-            self.load_plugins("replaygain")
-        except Exception:
-            self.teardown_beets()
-            self.unload_plugins()
-
     def _add_album(self, *args, **kwargs):
         # Use a file with non-zero volume (most test assets are total silence)
         album = self.add_album_fixture(*args, fname=self.FNAME, **kwargs)
@@ -109,10 +125,6 @@ class ReplayGainCliTestBase(TestHelper):
 
         return album
 
-    def tearDown(self):
-        self.teardown_beets()
-        self.unload_plugins()
-
     def test_cli_saves_track_gain(self):
         self._add_album(2)
 
@@ -320,55 +332,33 @@ class ReplayGainCliTestBase(TestHelper):
 
 @unittest.skipIf(not GST_AVAILABLE, "gstreamer cannot be found")
 class ReplayGainGstCliTest(
-    ReplayGainCliTestBase, unittest.TestCase, GstBackendMixin
+    ReplayGainCliTest, ReplayGainTestCase, GstBackendMixin
 ):
     FNAME = "full"  # file contains only silence
 
 
 @unittest.skipIf(not GAIN_PROG_AVAILABLE, "no *gain command found")
 class ReplayGainCmdCliTest(
-    ReplayGainCliTestBase, unittest.TestCase, CmdBackendMixin
+    ReplayGainCliTest, ReplayGainTestCase, CmdBackendMixin
 ):
     FNAME = "full"  # file contains only silence
 
 
 @unittest.skipIf(not FFMPEG_AVAILABLE, "ffmpeg cannot be found")
 class ReplayGainFfmpegCliTest(
-    ReplayGainCliTestBase, unittest.TestCase, FfmpegBackendMixin
+    ReplayGainCliTest, ReplayGainTestCase, FfmpegBackendMixin
 ):
     FNAME = "full"  # file contains only silence
 
 
 @unittest.skipIf(not FFMPEG_AVAILABLE, "ffmpeg cannot be found")
 class ReplayGainFfmpegNoiseCliTest(
-    ReplayGainCliTestBase, unittest.TestCase, FfmpegBackendMixin
+    ReplayGainCliTest, ReplayGainTestCase, FfmpegBackendMixin
 ):
     FNAME = "whitenoise"
 
 
-class ImportTest(TestHelper):
-    threaded = False
-
-    def setUp(self):
-        # Implemented by Mixins, see above. This may decide to skip the test.
-        self.test_backend()
-
-        self.setup_beets(disk=True)
-        self.config["threaded"] = self.threaded
-        self.config["replaygain"]["backend"] = self.backend
-
-        try:
-            self.load_plugins("replaygain")
-        except Exception:
-            self.teardown_beets()
-            self.unload_plugins()
-
-        self.importer = self.create_importer()
-
-    def tearDown(self):
-        self.unload_plugins()
-        self.teardown_beets()
-
+class ImportTest:
     def test_import_converted(self):
         self.importer.run()
         for item in self.lib.items():
@@ -380,27 +370,27 @@ class ImportTest(TestHelper):
 
 
 @unittest.skipIf(not GST_AVAILABLE, "gstreamer cannot be found")
-class ReplayGainGstImportTest(ImportTest, unittest.TestCase, GstBackendMixin):
+class ReplayGainGstImportTest(ImportTest, ReplayGainTestCase, GstBackendMixin):
     pass
 
 
 @unittest.skipIf(not GAIN_PROG_AVAILABLE, "no *gain command found")
-class ReplayGainCmdImportTest(ImportTest, unittest.TestCase, CmdBackendMixin):
+class ReplayGainCmdImportTest(ImportTest, ReplayGainTestCase, CmdBackendMixin):
     pass
 
 
 @unittest.skipIf(not FFMPEG_AVAILABLE, "ffmpeg cannot be found")
 class ReplayGainFfmpegImportTest(
-    ImportTest, unittest.TestCase, FfmpegBackendMixin
+    ImportTest, ReplayGainTestCase, FfmpegBackendMixin
 ):
     pass
 
 
 @unittest.skipIf(not FFMPEG_AVAILABLE, "ffmpeg cannot be found")
 class ReplayGainFfmpegThreadedImportTest(
-    ImportTest, unittest.TestCase, FfmpegBackendMixin
+    ThreadedImportMixin, ImportTest, ReplayGainTestCase, FfmpegBackendMixin
 ):
-    threaded = True
+    pass
 
 
 def suite():
@@ -409,3 +399,4 @@ def suite():
 
 if __name__ == "__main__":
     unittest.main(defaultTest="suite")
+    unittest.main(defaultTest="suite")