What are decorators in Python — what are they, and where are they used in tests?

Decorators in Python are functions that take another function and return a new function with extended behavior, without modifying the original code.

In tests, decorators are often used for:

• Reusing code (for example, setting up the environment before a test).
• Logging or measuring the execution time of tests.
• Skipping tests under certain conditions.

An example of using a decorator to skip a test if a condition is not met:

import unittest

def skip_if_no_db(func):
    def wrapper(*args, **kwargs):
        if not check_db_connection():
            raise unittest.SkipTest("No database connection")
        return func(*args, **kwargs)
    return wrapper

class MyTests(unittest.TestCase):
    @skip_if_no_db
    def test_query(self):
        # test that requires a database
        pass

Thus, decorators help make tests more flexible and readable.