diff --git a/tests/test_engine.py b/tests/test_engine.py
index c406d2577..b2d1d83c7 100644
--- a/tests/test_engine.py
+++ b/tests/test_engine.py
@@ -97,13 +97,11 @@ except ImportError:
 else:
     TestDataClass = make_dataclass("TestDataClass", [("name", str), ("url", str), ("price", int)])
 
-    class _dataclass_spider(DictItemsSpider):
+    class DataClassItemsSpider(DictItemsSpider):  # type: ignore[no-redef]
         def parse_item(self, response):
             item = super().parse_item(response)
             return TestDataClass(**item)
 
-    DataClassItemsSpider = _dataclass_spider
-
 
 class ItemZeroDivisionErrorSpider(TestSpider):
     custom_settings = {
diff --git a/tox.ini b/tox.ini
index 353977519..5b0606f8f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -37,7 +37,7 @@ basepython = python3
 deps =
     mypy==0.780
 commands =
-    mypy {posargs: scrapy tests}
+    mypy --show-error-codes {posargs: scrapy tests}
 
 [testenv:security]
 basepython = python3