Suppress unittest lifecycle methods in test files

README.md

@@ -158,6 +158,10 @@ def foo():  # noqa: DC02
 
 A comment on the first decorator line is still accepted.
 
+## Ignoring unittest lifecycle methods
+`unittest` lifecycle methods (`setUp`, `tearDown`, `setUpClass`, `tearDownClass`, `asyncSetUp`, `asyncTearDown`, `setUpModule`, `tearDownModule`) declared in test files are ignored by default, alongside the existing pytest hooks.
+Declarations with those names outside test files are still reported as unused code.
+
 ## Contributing
 
 Create a feature branch from `main`, open a pull request targeting `main`, and
@@ -266,6 +270,7 @@ the public module-level names are exported.
         - --ignore-bodies-if-inherits-from and --ignore-definitions-if-inherits-from now recognize dotted base classes such as graphene.ObjectType and match their final component.
         - The option help text and README document the accepted plain, dotted and glob base-name forms.
         - Render decorator names deterministically, including dotted names, and stop unusual decorators such as `@Class().function()` from crashing or producing memory addresses.
+        - Stop reporting unittest lifecycle methods declared in test files as unused code (issue #21).
 - v2.5.0 (2026-11-07):
     - Bugfixes:
         - Fix a crash when a decorator has no `id` attribute.

deadcode/visitor/ignore.py

@@ -19,6 +19,18 @@
     'setup_method',
     'teardown_method',
 }
+UNITTEST_METHOD_NAMES = {
+    'setUp',
+    'tearDown',
+    'setUpClass',
+    'tearDownClass',
+    'asyncSetUp',
+    'asyncTearDown',
+}
+UNITTEST_FUNCTION_NAMES = {
+    'setUpModule',
+    'tearDownModule',
+}
 
 ERROR_CODES = {
     'variable': b'DC01',
@@ -88,12 +100,20 @@ def _ignore_import(filename: Path, import_name: str) -> bool:
 
 
 def _ignore_function(filename: Path, function_name: str) -> bool:
-    return (function_name in PYTEST_FUNCTION_NAMES or function_name.startswith('test_')) and _is_test_file(filename)
+    # Class-level lifecycle methods such as `def setUpClass(cls)` have no decorator and a first argument other
+    # than `self`, so `visit_FunctionDef` classifies them as functions and they must be suppressed here as well.
+    return (
+        function_name in PYTEST_FUNCTION_NAMES
+        or function_name in UNITTEST_METHOD_NAMES
+        or function_name in UNITTEST_FUNCTION_NAMES
+        or function_name.startswith('test_')
+    ) and _is_test_file(filename)
 
 
 def _ignore_method(filename: Path, method_name: str) -> bool:
     return _is_special_name(method_name) or (
-        (method_name in PYTEST_METHOD_NAMES or method_name.startswith('test_')) and _is_test_file(filename)
+        (method_name in PYTEST_METHOD_NAMES or method_name in UNITTEST_METHOD_NAMES or method_name.startswith('test_'))
+        and _is_test_file(filename)
     )
 
 

tests/test_unittest_lifecycle_methods.py

@@ -0,0 +1,76 @@
+from pathlib import Path
+
+import pytest
+
+from deadcode.cli import main, print_main
+from deadcode.utils.base_test_case import BaseTestCase
+
+SOURCE = b"""
+from unittest import TestCase
+
+
+class MyTests(TestCase):
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def setUpClass(cls):
+        pass
+
+    def tearDownClass(cls):
+        pass
+
+    def test_something(self):
+        pass
+"""
+
+SOURCE_WITH_UNUSED_HELPER = (
+    SOURCE
+    + b"""
+    def unused_helper(self):
+        pass
+"""
+)
+
+
+class TestUnittestLifecycleMethods(BaseTestCase):
+    def test_lifecycle_methods_in_test_file_are_not_reported(self):
+        self.files = {'/project/tests/test_sample.py': SOURCE}
+
+        self.assertIsNone(main(['/project/tests/test_sample.py', '--no-color']))
+        self.assertEqual(print_main(['/project/tests/test_sample.py', '--no-color']), 0)
+
+    def test_lifecycle_methods_outside_test_file_are_still_reported(self):
+        self.files = {'/project/sample.py': SOURCE}
+
+        output = main(['/project/sample.py', '--no-color'])
+
+        assert output is not None
+        self.assertIn('DC04 Method `setUp` is never used', output)
+        self.assertIn('DC04 Method `tearDown` is never used', output)
+        self.assertIn('DC02 Function `setUpClass` is never used', output)
+        self.assertIn('DC02 Function `tearDownClass` is never used', output)
+        self.assertEqual(print_main(['/project/sample.py', '--no-color']), 1)
+
+    def test_unrelated_unused_method_in_test_file_is_still_reported(self):
+        self.files = {'/project/tests/test_sample.py': SOURCE_WITH_UNUSED_HELPER}
+
+        output = main(['/project/tests/test_sample.py', '--no-color'])
+
+        assert output is not None
+        self.assertEqual(len(output.splitlines()), 1)
+        self.assertTrue(output.endswith('DC04 Method `unused_helper` is never used'))
+
+
+def test_unittest_lifecycle_in_temporary_test_directory_returns_no_findings(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    test_directory = tmp_path / 'tests'
+    test_directory.mkdir()
+    (test_directory / 'test_sample.py').write_bytes(SOURCE)
+    monkeypatch.chdir(tmp_path)
+
+    assert main(['tests', '--no-color']) is None
+    assert print_main(['tests', '--no-color']) == 0