This rule raises an issue when a method in a test class is not discoverable as a test and is never used within its test class.

Why is this an issue?

As classes subclassing unittest.TestCase or unittest.IsolatedAsyncioTestCase will be executed as tests, they should define test methods and not be used as "abstract" parent helper. Methods within the class will be discovered by the test runner if their name starts with test. If a method intended to be a test does not respect this convention, it will not be executed.

For a class to be considered a test case, it should subclass only unittest.TestCase or unittest.IsolatedAsyncioTestCase. If it subclasses other classes, it might be a mixin. This rule raises an issue when a method is not discoverable as a test and is never used within its test case class.

This rule will not raise if:

• The method is called directly from another method.
• The method overrides an existing method in the parent class (example: a tearDown or asyncSetUp method).

Noncompliant code example

import unittest
class MyTest(unittest.TestCase):
  def setUp(self): ... # OK (unittest.TestCase method)
  def something_test(self): ... # Noncompliant

Compliant solution

import unittest
class MyTest(unittest.TestCase):
  def setUp(self): ...
  def test_something(self): ...