Kudos Software Engineer Interview Task

This repository contains a simple web server, written in Python. When running, the server exposes a simple REST-style API. You'll be adding a small new feature to this server. Don't worry if you haven't used Python before, or written web server code. The goal of the exercise is demonstrate your ability to read and understand a codebase that you're new to, before extending what's already there.

Getting Started

First of all, you'll need a copy of this codebase to work on. You can download the code as a Zip file from the 'Code' menu on GitHub, or clone it directly using Git (if you're comfortable using it).

Installing Python

You'll need to have a recent version of Python 3 installed. This code was written for Python 3.9 or newer. You can download Python for Windows, Linux, and macOS on the official Python downloads page. During Python setup on Windows, you'll have the option to 'Add Python 3.x to PATH' – you should make sure this is enabled. After installing Python on Windows, log out or restart your computer to make sure PATH changes take effect.

You can check if Python is installed properly by running the following command on Linux and macOS (in a terminal):

python3 --version

Or on Windows (CMD/Command Prompt or PowerShell):

python --version

You should see the installed version of Python printed in the terminal. If you see an error, Python 3 is not installed correctly.

Creating a virtual environment

A virtual environment will allow you to install the packages this code requires without affecting your system Python installation. Make sure your working directory is the top-level directory of the interview task codebase you downloaded (the same directory as this README.md file).

First, create the virtual environment by running the following command on Linux or macOS:

python3 -m venv reminders-env

Or on Windows (CMD/Command Prompt or PowerShell):

python -m venv reminders-env

This tells Python to create a new virtual environment in the 'reminders-env' directory. To use the virtual environment, you need to activate it by running the following command.

On Linux and macOS:

source reminders-env/bin/activate

Or on Windows CMD/Command Prompt:

reminders-env\Scripts\activate.bat

Or on Windows PowerShell:

reminders-env\Scripts\Activate.ps1

You'll see the prompt change to reflect that you've activated the virtual environment. While the virtual environment is active, all Python commands such as python3 and pip will only affect the virtual environment.

You should run all subsequent commands while working on this task with the virtual environment active.

Install the required third-party packages

We can use pip to automatically download and install all the needed requirements for this project. Run the following command (on Linux, macOS, Windows CMD/Command Prompt, and Windows PowerShell):

pip install -r requirements.txt

You'll see pip install the packages listed in requirements.txt, along with any additional packages that are needed.

Run the server

Let's run the server and manually test its API endpoints. To run the server, run the following command on Linux or macOS:

FLASK_APP=reminders flask run

Or on Windows CMD/Command Prompt, run the following two commands:

set FLASK_APP=reminders
flask run

Or on Windows PowerShell, run the following two commands:

$env:FLASK_APP='reminders'
flask run

This tells Flask to discover our app inside the reminders package and run its local development server. You should see the following message:

 * Serving Flask app 'reminders' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

(If you see a different address in the 'Running on' line, just substitute that address in the commands that follow.)

In a separate terminal (or command prompt window), activate the virtual environment. You can then use a package called HTTPie that was installed by pip to excercise the app's API. Here's an example that shows how to list all current reminders, then create a new one, then check the list again. Lines typed are prefixed with $, and the results of each command are given verbatim. All commands are the same for Linux, macOS, Windows CMD/Command Prompt, and Windows PowerShell

1. Listing current reminders

$ http get http://127.0.0.1:5000/reminders

HTTP/1.0 200 OK
Content-Type: application/json

[
    {
        "priority": 1,
        "title": "Re-paint the living room"
    },
    {
        "priority": 2,
        "title": "Learn some Python"
    },
    {
        "priority": 3,
        "title": "Complete the interview task"
    }
]

2. Creating a new reminder

This one uses the --verbose flag so you can see the JSON request body that HTTPie constructs from the arguments given.

http --verbose post  http://127.0.0.1:5000/reminders title="My new reminder" priority:=3
POST /reminders HTTP/1.1
Accept: application/json, */*;q=0.5
Content-Type: application/json

{
    "priority": 3,
    "title": "My new reminder"
}


HTTP/1.0 201 CREATED
Content-Type: application/json

{
    "priority": 3,
    "title": "My new reminder"
}

3. Checking current reminders

$ http get http://127.0.0.1:5000/reminders

HTTP/1.0 200 OK
Content-Type: application/json

[
    {
        "priority": 1,
        "title": "Re-paint the living room"
    },
    {
        "priority": 2,
        "title": "Learn some Python"
    },
    {
        "priority": 3,
        "title": "Complete the interview task"
    },
    {
        "priority": 3,
        "title": "My new reminder"
    }
]

As you make requests, the terminal window will show debugging output from Flask, including details of any errors that occur. If you're trying to figure out why something isn't working, this is a good place to check!

Once you're done with the web server, you can stop it by typing Ctrl-C in the terminal window where the server is running.

Running the automated tests

The app has a small suite of automated tests that will make sure its current features are working as intended. These tests use pytest to run them and report feedback. Pytest will automatically discover and run these tests, so long as your working directory is the same folder as this README.md file.

In a terminal with the virtual environment activated, run the following command on Linux or macOS:

python3 -m pytest

Or on Windows CMD/Command Prompt, or Windows PowerShell:

python -m pytest

You'll see pytest report the test results:

=== test session starts ===
platform yourplatform -- Python 3.x.y, pytest-7.1.1, pluggy-1.0.0
rootdir: /path/to/interview-task
collected 8 items

tests/test_models.py .. [ 25%]
tests/test_routes.py ...... [100%]

=== 8 passed in 0.05s ===

If a test fails, pytest will report which assertion didn't succeed to help with debugging.

Task to complete

We want to extend the list reminders API endpoint at /reminders so that users can list only reminders with a given priority. The priority will be given as a query parameter in the request URL called priority. With the default reminders that are loaded when the server starts, we should be able to use the following HTTPie command and get the result below:

$ http get http://127.0.0.1:5000/reminders?priority=3

HTTP/1.0 200 OK
Content-Type: application/json

[
    {
        "priority": 3,
        "title": "Complete the interview task"
    }
]

Some tips to get you started:

• You can access the query parameters within a Flask route using request.args
• You can find the code for all the routes in reminders/__init__.py
• Don't worry too much about writing idiomatic Python code (unless you want to!); this exercise isn't really about Python, but more the way in which you approach making a change to an existing codebase
• You should consider how you and others will test your changes.
• Don't worry if there's aspects you struggle with or are uncertain about. The goal of this task is to give us insight into the way you think and solve problems, so don't worry about submitting the code, even if you feel it's incomplete or there's aspects you could improve upon.

Submitting your work

Please submit your work by creating a zip archive of the entire repository, except for the reminders-env and __pycache__ folders (if present).

If you're using macOS or Linux, you can use the following command from the directory containing the interview-task repository (one level above this README.md file) to automatically exclude unnecessary files:

zip -r completed-interview-task.zip interview-task -x "*/reminders-env/*" -x "*/__pycache__/*" -x "*/.*/*"

(This command assumes that the directory containing the code is called interview-task – if not, you'll need to adjust the above command.)

This will help to keep the size of the zip file down. Email your completed task to engineering@growkudos.com with the subject 'Engineering interview code submission for <YOUR NAME HERE>'.

Project Structure

Here's a description of the way the project is laid out:

• README.md – that's this file!
• requirements.txt – lists the Python packages this project needs.
• reminders/ – contains the web application code
  • init.py – contains the setup code for the app along with the code that handles HTTP requests on each route
  • models.py – contains the Reminder model class that represents individual reminders inside the app
  • serialization.py – contains code that converts Reminder instances into simple Python lists and dicts, ready to be used in a JSON response from a Flask route
• tests/ – contains the automated test code¹
  • conftest.py – contains test configuration, including pytest fixtures to automate setting up common test requirements
  • test_models.py – contains tests for the models in reminders/models.py
  • test_routes.py – contains tests for the API endpoints

¹ pytest will automatically discover all test functions in the tests/ directory, so long as:

• They are in a file with a name that starts with test_
• The function name also starts with test_

This allows you to include test helper functions if needed – just make sure they don't start with test_!

Questions

If you have any questions at all about this task, want feedback, or some tips, please don't hesitate to reach out to your Kudos contact to ask questions!