Manage test environments

When writing tests that interact with environment variables or configuration settings, always (1) preserve the original state and (2) explicitly specify required configurations.

For environment variables, use setUp/tearDown methods to save and restore their state after test execution:

def restore_dict(self, dictionary: dict, original_data: dict):
    dictionary.clear()
    dictionary.update(original_data)

def setUp(self):
    # Save original environment to restore after test
    original_env = os.environ.copy()
    self.addCleanup(lambda: self.restore_dict(os.environ, original_env))

For service configurations, always explicitly specify required parameters like region rather than relying on the machine’s environment:

self.session = boto3.session.Session(region_name='us-west-2')

This practice ensures tests are isolated, repeatable, and portable across different development environments, preventing unexpected test failures and interference between test cases.