One-to-many Object Relationships Lab

Learning Goals

Create a one-to-many relationship.

Key Vocab

Class: a bundle of data and functionality. Can be copied and modified to accomplish a wide variety of programming tasks.
Object: the more common name for an instance. The two can usually be used interchangeably.
Object-Oriented Programming: programming that is oriented around data (made mobile and changeable in objects) rather than functionality. Python is an object-oriented programming language.
Function: a series of steps that create, transform, and move data.
Method: a function that is defined inside of a class.

Introduction

In this lab we will implement a one-to-many relationship between a Owner and Pet.

Instructions

This is a test-driven lab. Run pipenv install to create your virtual environment and pipenv shell to enter the virtual environment. Then run pytest -x to run your tests. Use these instructions and pytest's error messages to complete your work in the lib/ folder.

Instructions:

Define an Owner class and pass into the constructor a name argument.
Define a Pet and pass into the constructor its name, pet_type and an optional owner.
Define a class variable PET_TYPES = ["dog", "cat", "rodent", "bird", "reptile", "exotic"] and validate that the pet_type is one of those types in the __init__ method.
- raise Exception if this check fails.
Define a class variable all that stores all instances of the Pet class.
In the Owner class write a method called pets(self) that returns a full list of the owner's pets.
In the Owner class write a method called add_pet(self, pet) that checks that the the pet is of type Pet and adds the owner to the pet.
In the Owner class write a method called get_sorted_pets(self) returns a sorted list of pets by their names.
Owner and Pet should use isinstance to check types whenever instances are passed into methods.
- raise Exception if these checks fail.

Resources