import unittest
import importlib

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)


class TestRegisterUser(unittest.TestCase):
    def setUp(self):
        """Reset users_db before each test"""
        import user_code
        user_code.users_db.clear()

    def test_successful_registration(self):
        import user_code
        try:
            result = user_code.register_user(
                username="Test",
                email="test@example.com",
                age=18
            )
            expected_output = "User Test registered successfully!"
            condition = result == expected_output
            failure_message = (
                "The success message should use the provided `username` parameter. "
                f"For input ('Test', 'test@example.com', 18), expected "
                f"`{expected_output}`, but got `{result}`."
            )
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."

        _dynamic_test(
            self,
            condition,
            "User is registered successfully with valid input.",
            failure_message
        )

    def test_user_count_after_registration(self):
        import user_code
        try:
            user_code.register_user("Test", "test@example.com", 18)
            condition = len(user_code.users_db) == 1
            failure_message = (
                "After one successful registration, `users_db` should contain exactly one user."
            )
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."

        _dynamic_test(
            self,
            condition,
            "User count after registration is correct.",
            failure_message
        )

    def test_user_data_after_registration(self):
        import user_code
        try:
            user_code.register_user("Test", "test@example.com", 18)
            registered_user = user_code.users_db[0]
            condition = (
                registered_user == {
                    "username": "Test",
                    "email": "test@example.com",
                    "age": 18
                }
            )
            failure_message = (
                "The user dictionary should be created from function parameters. "
                "Expected {'username': username, 'email': email, 'age': age} "
                f"but got {registered_user}."
            )
        except Exception:
            condition = False
            failure_message = (
                "User data was not stored correctly in `users_db`."
            )

        _dynamic_test(
            self,
            condition,
            "User data is stored correctly using function parameters.",
            failure_message
        )

    def test_underage_registration(self):
        import user_code
        try:
            result = user_code.register_user("Test", "test@example.com", 16)
            expected_output = "Registration failed: age must be 18 or older."
            condition = result == expected_output and len(user_code.users_db) == 0
            failure_message = (
                "Users under 18 should not be registered and `users_db` must remain empty."
            )
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."

        _dynamic_test(
            self,
            condition,
            "Underage users are blocked correctly.",
            failure_message
        )

    def test_multiple_registrations(self):
        import user_code
        try:
            user_code.register_user("Test", "test@example.com", 18)
            user_code.register_user("Another", "another@example.com", 30)
            condition = len(user_code.users_db) == 2
            failure_message = (
                "Each call to `register_user` should append a new user to `users_db`."
            )
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."

        _dynamic_test(
            self,
            condition,
            "Multiple users can be registered successfully.",
            failure_message
        )

    def test_users_db_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "users_db"),
            "The `users_db` variable is declared.",
            "Expected `users_db` to be declared."
        )


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


test_main.py

Gain a solid understanding of how functions shape Python programming. Master defining and calling functions, working with arguments, handling return values, and creating flexible, efficient code using recursion and lambda expressions.

Explore what functions are and why they're essential in Python. Learn how to create functions, define arguments, handle return values, and use built-in functions effectively.

Learn how positional and optional arguments work in Python. Build adaptable functions that handle different inputs and improve flexibility in your code.

Understand how to work with arbitrary and keyword arguments to handle variable input sizes. Learn how these techniques make your functions more dynamic and organized.

Discover how return values represent a function's output. Learn to return single or multiple values, use None, and explore generators for more advanced data flow control.

Unlock advanced function concepts with recursion and lambda functions. Learn how recursion solves repetitive problems and how lambda expressions create concise, one-line functions.

Challenge: Positional Arguments

Solution

Challenge: Positional Arguments

Solution