Hello! In this quest, we're going to make another special helper in Python, just like our add function. This time, it will be a multiply function!
Our multiply function will take two numbers and give us back their product (that's what you get when you multiply them). We'll put this function in a file called operations.py.
Now it's your turn to write the code! We need to make the multiply function inside operations.py work.
Remember, a function is like a mini-program that does a specific job. Our multiply function needs to take two numbers and give back their product.
Here's an example of how you might make a function that adds two numbers. You can use this idea to help you with your multiply function:
def add(num1, num2):
# This function takes two numbers and adds them.
total = num1 + num2
return total
Your task is to complete the multiply function so it correctly multiplies the two numbers it receives.
Now that you've started your multiply function, it's time to write your own tests! This is a very important step because it helps you make sure your code works correctly.
Create a new file called test_operations.py in the same folder as your operations.py file.
Inside test_operations.py, you'll write test functions that check if your multiply function gives the right answers. Here are some ideas for tests you should write:
multiply(2, 3) gives 6 and multiply(10, 5) gives 50.multiply(-2, -3) gives 6 and multiply(-4, -5) gives 20.multiply(5, -2) gives -10 and multiply(-3, 4) gives -12.multiply(0, 7), multiply(9, 0), and multiply(0, 0). They should all give 0.multiply(2.5, 2.0) which should give 5.0, and multiply(1.5, 3.0) which should give 4.5.Remember to use assert to check if your function's answer matches what you expect!
# Example of a test function structure
import pytest # You'll need this if you use pytest.approx()
from operations import multiply # This brings your multiply function into the test file
def test_example_case():
# Call your function and check the result
assert multiply(some_number, another_number) == expected_answer
Once you've written your tests, save the test_operations.py file. You're doing great!
Now that you've written your multiply function and created your own tests in test_operations.py, let's run the tests to see if everything is working correctly!
Open your terminal and type this command:
pytest module-1.1/blueprint-6/quest-20
What you should see:
If all your tests show ✅, it means your multiply function is working perfectly and your tests are doing a great job of checking it!
Now, let's review your code with your mentor. Be ready to talk about:
multiply function.test_operations.py file.multiply function.This document provides a quick reference for defining Python functions and writing basic tests using pytest.
A function is a block of code that performs a specific task. You define a function using the def keyword.
def function_name(parameter1, parameter2):
"""
This is a docstring. It explains what the function does.
Args:
parameter1: Description of the first parameter.
parameter2: Description of the second parameter.
Returns:
Description of the value the function returns.
"""
# Function body starts here, indented
# Code to perform the task
result = parameter1 + parameter2
return result # Use return to send a value back
def: Keyword to start a function definition.function_name: Choose a descriptive name.(parameter1, parameter2): Input values the function accepts. Can be zero or more.:: Marks the end of the function header."""..."""): Explains the function's purpose, arguments (Args), and return value (Returns). Good practice for documentation.return: Sends a value back from the function. If return is not used, the function returns None by default.
Testing helps verify that your code works as expected. pytest is a framework for writing and running tests in Python.
test_ or ending with _test.py.test_.
A test function calls the code you want to test and uses assert statements to check if the results are correct.
# Example test function structure
def test_something():
# Call the function you are testing
actual_result = your_function(input_value)
# Use assert to check if the actual result matches the expected result
assert actual_result == expected_result
def test_...: Defines a test function. pytest finds and runs functions named this way.assert condition: Checks if condition is True. If it's False, the test fails.
You can include multiple assert statements within a single test function to check different inputs or cases for the same function.
# Example test function with multiple assertions
def test_example_function():
# Test case 1: Positive input
assert example_function(5) == 25
# Test case 2: Negative input
assert example_function(-3) == 9
# Test case 3: Zero input
assert example_function(0) == 0
This approach helps ensure your function handles various situations correctly. If any assert fails, the test function stops and is marked as failed.
Navigate to your project directory in the terminal and run the command:
pytest
pytest will discover and run your test files and functions, reporting the results (PASSED, FAILED, etc.).
