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):
        """Checks that a user is successfully registered with valid data"""
        import user_code
        try:
            result = user_code.register_user(username="Alice", email="alice@example.com", age=18)
            expected_output = "User Alice registered successfully!"
            condition = result == expected_output
            failure_message = f"For input `('Alice', 'alice@example.com', 18)`, expected `{expected_output}`, but got `{result}`."
        
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."
        
        _dynamic_test(self, condition, "The `register_user` function registers a user correctly.", failure_message)
    
    def test_user_count_after_registration(self):
        """Checks that the number of users in the database is correct after a successful registration"""
        import user_code
        try:
            user_code.register_user(username="Alice", email="alice@example.com", age=18)
            condition = len(user_code.users_db) == 1
            failure_message = f"For input `('Alice', 'alice@example.com', 18)`, expected 1 user in the database, but found {len(user_code.users_db)}."
        
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."
        
        _dynamic_test(self, condition, "The number of registered users is correct.", failure_message)
    
    def test_user_data_after_registration(self):
        """Checks that the user data is correctly added to the database after a successful registration"""
        import user_code
        try:
            user_code.register_user(username="Alice", email="alice@example.com", age=18)
            registered_user = user_code.users_db[0]
            condition = (registered_user["username"] == "Alice" and
                         registered_user["email"] == "alice@example.com" and
                         registered_user["age"] == 18)
            failure_message = f"For input `('Alice', 'alice@example.com', 18)`, expected user data `{{'username': 'Alice', 'email': 'alice@example.com', 'age': 18}}` in `users_db`, but got {registered_user}."
        
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."
        except Exception:
            condition = False
            failure_message = "For input `('Alice', 'alice@example.com', 18)`, expected user data `{{'username': 'Alice', 'email': 'alice@example.com', 'age': 18}}` in `users_db`, but this element won't be found there."
        
        _dynamic_test(self, condition, "The user data is correctly stored in the database.", failure_message)
    
    def test_underage_registration(self):
        """Checks that users under 18 cannot register"""
        import user_code
        try:
            result = user_code.register_user(username="Bob", email="bob@example.com", age=16)
            expected_output = "Registration failed: age must be 18 or older."
            condition = result == expected_output and len(user_code.users_db) == 0
            failure_message = f"For input `('Bob', 'bob@example.com', 16)`, expected `{expected_output}`, but got `{result}`."
        
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."
        
        _dynamic_test(self, condition, "The `register_user` function correctly blocks underage users.", failure_message)
    
    def test_multiple_registrations(self):
        """Checks that multiple users can be registered"""
        import user_code
        try:
            user_code.register_user(username="Alice", email="alice@example.com", age=18)
            user_code.register_user(username="Charlie", email="charlie@example.com", age=30)
            condition = len(user_code.users_db) == 2
            failure_message = f"For input registrations `('Alice', 'alice@example.com', 18)` and `('Charlie', 'charlie@example.com', 30)`, expected 2 users, but found {len(user_code.users_db)}."
        
        except AttributeError:
            condition = False
            failure_message = "The function `register_user` is not defined."
        
        _dynamic_test(self, condition, "The `register_user` function allows multiple users to register.", 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

You'll have a solid grasp of how important functions are in Python, no matter your field in computer science. We'll cover creating functions, defining arguments, handling return values, and exploring their use in Python.

We will consider what a function in Python and some basic techniques used to create functions is: what are the arguments of the function, what is the return value of the function, what is the body of the function, and how to use the function in the code.

Learn how to define functions in Python using positional and optional arguments. Master the flexibility of creating functions that adapt to different input scenarios.

Learn to work with arbitrary arguments and keyword arguments in Python to handle variable numbers of inputs. Understand how arbitrary arguments manage flexible positional inputs and how keyword arguments organize named arguments into a dictionary for efficient function design.

The return value of a function is the direct result of the execution of the function, which we can use in the program. There are several types of function return values - we will consider the most commonly used.

Explore the power of recursion and lambda functions in Python. Understand how recursion allows a function to call itself for solving complex problems, and how lambda functions provide a concise way to define anonymous functions for simple tasks.

Challenge: Positional Arguments

Solution

Awesome!

Challenge: Positional Arguments

Solution

Awesome!