How do I test Python decorators?

How do I test Python decorators?

To test Python decorators, you can use the unittest framework. You can create a test case that applies the decorator to a function and then checks the output.

Can you show me an example of a test for a simple decorator?

Sure! Here's a simple example:

def my_decorator(func):
    def wrapper():
        return 'Hello, ' + func()  
    return wrapper

@my_decorator
def greet():
    return 'World'

# Test
import unittest

class TestMyDecorator(unittest.TestCase):
    def test_greet(self):
        self.assertEqual(greet(), 'Hello, World')

if __name__ == '__main__':
    unittest.main()

What if my decorator takes arguments?

If your decorator takes arguments, you can create a nested function to handle those arguments. You would then test it similarly by applying the decorator to a function that uses those arguments.

Can you provide an example of a decorator with arguments?

Absolutely! Here's an example:

def repeat(num_times):
    def decorator_repeat(func):
        def wrapper(*args, **kwargs):
            for _ in range(num_times):
                func(*args, **kwargs)
        return wrapper
    return decorator_repeat

@repeat(3)
def say_hello():
    print('Hello!')

# Test
import unittest
from unittest.mock import patch

class TestRepeatDecorator(unittest.TestCase):
    @patch('builtins.print')
    def test_say_hello(self, mock_print):
        say_hello()
        self.assertEqual(mock_print.call_count, 3)

if __name__ == '__main__':
    unittest.main()