diff --git a/scrapy/utils/response.py b/scrapy/utils/response.py
index fd0b59de4..4acc77111 100644
--- a/scrapy/utils/response.py
+++ b/scrapy/utils/response.py
@@ -61,7 +61,6 @@ _mime_overrides = get_data('scrapy', 'mime.types') or b''
 _MIME_TYPES.readfp(StringIO(_mime_overrides.decode()))
 
 
-
 def _is_html_mime_type(mime_type):
     if mime_type in {
         b'application/xhtml+xml',
diff --git a/tests/test_responsetypes.py b/tests/test_responsetypes.py
index 0b6be7f85..3d5217385 100644
--- a/tests/test_responsetypes.py
+++ b/tests/test_responsetypes.py
@@ -1,5 +1,4 @@
 import unittest
-from warnings import catch_warnings
 
 import pytest
 
@@ -10,7 +9,7 @@ from scrapy.http import (
     TextResponse,
     XmlResponse,
 )
-from scrapy.responsetypes import responsetypes, ResponseTypes
+from scrapy.responsetypes import responsetypes
 from .test_utils_response import (
     POST_XTRACTMIME_SCENARIOS,
     PRE_XTRACTMIME_SCENARIOS,