Use modern assertions

Always use current assertion methods in test code to ensure clarity and future compatibility. Specifically, replace deprecated methods with their modern equivalents, such as using assertRaisesRegex instead of assertRaisesRegexp when validating exceptions. This approach allows you to verify both the exception type and the specific error message content in a single assertion.

# Bad
with self.assertRaisesRegexp(ValueError, "expected message"):
    function_that_raises()

# Good
with self.assertRaisesRegex(ValueError, "expected message"):
    function_that_raises()

By using modern assertion methods, you improve test readability and maintainability while ensuring your tests will continue to work with future framework updates.