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# Function Assertions

In this notebook, you'll learn how to use most used Functions checking assertion functions. Below are the functions that I've covered in this notebook.

  1. assert_student_function_name_equals(student_function_name, fn_args=None, fn_kwargs=None, expected_value=DataWarsConstants.EMPTY): Checks that the student's function named student_function_name returns the expected value.
  2. assert_student_function_test_cases(student_function_name, test_cases): Checks that the student's function named student_function_name returns the expected value for each test case in the list test_cases.
  3. assert_student_function_test_cases_dictionary(student_function_name, test_cases): Similar to assert_student_function_test_cases, but each test case is a dictionary in the list test_cases. This allows you to specify positional and keyword arguments, expected return values, or expected exceptions (with optional messages).

Load the utils.py file to use the assertion functions.

exec(open("utils.py").read())

# Activities

Now, with activities examples, you'll learn how to use the assertion functions.

# 1. Create a function add().

Create a functions add() that takes two arguments and returns the sum of the two arguments.

def add(a, b):
    pass

Solution:

def add(a, b):
    return a + b

Out expected function should return the sum of the two arguments. So, we use assert_student_function_name_equals() function to assert the solution with the student function.

Assertions:

assert_student_function_name_equals('add', (2, 6), expected_value=8)
# 2. Implement a Function to Define a Movie Dictionary

Define a function define_movies that takes a dictionary, id, name, year, and rank as arguments and returns the dictionary with the movie details. Function also takes empty dictionary as first argument which will be used to store the movie details.

movies = {}

def define_movies(dictionary, id, name, year, rank):
    # Your code goes here
    return dictionary

Solution:

def define_movies(dictionary, id, name, year, rank):
    dictionary[id] = {
        'name': name,
        'year': year,
        'rank': rank
    }
    return dictionary
define_movies(movies, 0, 'Carmencita', 1894, 5.6)

Here we have two expected outputs, so we save them in two different dictionaries and then use assert_student_function_test_cases() function to assert the solution with the student function. Assertions:

# For the function `define_movies()`
expedted_movies_1 = {}
expedted_movies_2 = {}

assert_student_function_test_cases(
    "define_movies",
    [
    student_function_test_case((expedted_movies_1, 0, 'Carmencita', 1894, 5.6), expected_value={0: {'name': 'Carmencita', 'year': 1894, 'rank': 5.6}}),
    student_function_test_case((expedted_movies_2, 0, 'Carmencita', 1894, 5.6), expected_value={0: {'name': 'Carmencita', 'year': 1894, 'rank': 5.6}}),
     
    #  Add one more in expected_movies_1
    student_function_test_case((expedted_movies_1, 1, 'Carmencita', 1894, 5.6), expected_value={0: {'name': 'Carmencita', 'year': 1894, 'rank': 5.6}, 1: {'name': 'Carmencita', 'year': 1894, 'rank': 5.6}}),
    ]
)
# 3. Define a function define_roles

Define a function define_roles that takes a dictionary, actor_id, and role as arguments and returns the dictionary with the actor's roles. Function also takes empty dictionary as first argument which will be used to store the actor's roles.

roles = {}

def define_roles(dictionary, actor_id, role):
    # Your code goes here
    return dictionary

Solution:

def define_roles(dictionary, actor_id, role):
    if actor_id in dictionary:
        dictionary[actor_id]['role'].append(role)
    else:
        dictionary[actor_id] = {
            'role': [role]
        }
    return dictionary
define_roles(roles, 4, 'Actor')
define_roles(roles, 4, 'Singer')
define_roles(roles, 3, 'Actor')

Here we have two expected outputs, so we save them in two different dictionaries and then use assert_student_function_test_cases() function to assert the solution with the student function.

Assertions:

# For the function `define_roles()`
expedted_roles_1 = {}
expedted_roles_2 = {}

assert_student_function_test_cases(
    "define_roles",
    [
    student_function_test_case((expedted_roles_1, 4, 'Actor'), expected_value={4: {'role': ['Actor']}}),
    student_function_test_case((expedted_roles_2, 4, 'Actor'), expected_value={4: {'role': ['Actor']}}),
     
    #  Add one more in expeted_roles_1
    student_function_test_case((expedted_roles_1, 4, 'Singer'), expected_value={4: {'role': ['Actor', 'Singer']}}),
    ]
)
# 4. Create a function divide_numbers

Create a function divide_numbers(a, b) that returns the result of a / b. Raise a ZeroDivisionError if b == 0.

def divide_numbers(a, b):
    # Your code here
    pass

Solution:

def divide_numbers(a, b):
    if b == 0:
        raise ZeroDivisionError("division by zero")
    return a / b

Here we use assert_student_function_test_cases_dictionary() to check return values and exception handling.

assert_student_function_test_cases_dictionary(
    "divide_numbers",
    [
        {"args": (10, 2), "return_value": 5.0},
        {"args": (5, 0), "exception": ZeroDivisionError, "exception_message": "division by zero"},
        {"args": (9, 3), "return_value": 3.0}
    ]
)

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