When creating a class in unittest, which class must it inherit from?

When creating a class in the unittest framework for Python, the class must inherit from unittest.TestCase. This is essential because unittest.TestCase provides the foundational methods and features required to define test cases effectively. By inheriting from this class, you gain access to methods like assertEqual, assertTrue, and assertFalse, which are crucial for verifying the outcomes of your tests.

Additionally, unittest.TestCase comes with a built-in mechanism for setting up and tearing down test environments through the setUp() and tearDown() methods. This ensures that each test runs in isolation, allowing for reliable and repeatable test execution.

The other options, while related to the testing framework, do not serve as the base class for individual test case definitions. For example, unittest.BaseCase is not a standard class used in unittest, and unittest.TestSuite is intended for aggregating multiple test cases for execution but is not used as a base class for creating a test case. Similarly, unittest.TestRunner is responsible for running the tests but does not pertain to the creation of a test case class. Thus, the correct choice is to inherit from unittest.TestCase.