Mock Code Challenge - National Parks (Object Relationships)

For this assignment, we'll be working with a national park planner-style domain.

We have three models: NationalPark, Visitor, and Trip.

For our purposes, a NationalPark has many Trips, a Visitor has many Trips, and a Trip belongs to a Visitor and to a NationalPark.

NationalPark - Visitor is a many to many relationship.

Note: You should draw your domain on paper or on a whiteboard before you start coding. Remember to identify a single source of truth for your data.

Topics

• Classes and Instances
• Class and Instance Methods
• Variable Scope
• Object Relationships
• lists and list Methods

Instructions

To get started, run pipenv install while inside of this directory.

Build out all of the methods listed in the deliverables. The methods are listed in a suggested order, but you can feel free to tackle the ones you think are easiest. Be careful: some of the later methods rely on earlier ones.

Remember! This code challenge has tests to help you check your work. You can run pytest to make sure your code is functional before submitting.

We've provided you with a tool that you can use to test your code. To use it, run python debug.py from the command line. This will start a ipdb session with your classes defined. You can test out the methods that you write here. You can add code to the debug.py file to define variables and create sample instances of your objects.

Writing error-free code is more important than completing all of the deliverables listed - prioritize writing methods that work over writing more methods that don't work. You should test your code in the console as you write.

Similarly, messy code that works is better than clean code that doesn't. First, prioritize getting things working. Then, if there is time at the end, refactor your code to adhere to best practices. When you encounter duplicated logic, extract it into a shared helper method.

Before you submit! Save and run your code to verify that it works as you expect. If you have any methods that are not working yet, feel free to leave comments describing your progress.

Deliverables

Write the following methods in the classes in the files provided. Feel free to build out any helper methods if needed.

Initializers and Properties

Visitor

• Visitor __init__(self, name)
  • Visitor should be initialized with a name
• Visitor property name
  • Return name
  • Names must be of type str
  • Names must be between 1 and 15 characters, inclusive
  • raise Exception if setter fails

NationalPark

• NationalPark __init__(self, name)
  • national_parks should be initialized with a name, as a string
• NationalPark property name
  • Returns the NationalPark's name
  • Should not be able to change after the NationalPark is created
  • raise Exception if setter fails
  • hint: hasattr()

Trip

• Trip __init__(self, visitor, national_park, start_date, end_date)
  • Trips should be initialized with a visitor, national_park, start_date(str), end_date(str)

Object Relationship Methods and Properties

Trip

• Trip property visitor
  • Returns the visitor object for that trip
  • Must be of type Visitor
  • raise Exception if setter fails
• Trip property national_park
  • Returns the NationalPark object for that trip
  • Must be of type NationalPark
  • raise Exception if setter fails

Visitors

• Visitor trips()
  • Returns a list of all trips for that visitor
  • The list of trips must contain type Trip
• Visitor national_parks()
  • Returns a unique list of all parks who that visitor has visited.
  • The list of national parks must contain type NationalPark

NationalPark

• NationalPark trips()
  • Returns a list of all trips planned for this national park
  • The list of trips must contain type trip
• NationalPark visitors()
  • Returns a unique list of all visitors a national park has recieved
  • The list of visitors must contain type Visitor

Aggregate and Association Methods

National Park

• NationalPark total_visits()
  • Returns the total number of times that park has been visited
• NationalPark best_visitor()
  • Returns the Visitor who has visited the park the most

Bonus: Aggregate and Association Method

• NationalPark classmethod most_visited()
  • returns the NationalPark instance that has received the most trips.
  • hint: will need a way to remember all NationalPark objects
  • hint: do you have a way to get the total visits to a park?
  • Uncomment lines 110-121 in the national_park_test file to run the test

Bonus: For any invalid inputs, raise an Exception.

• If using pytest, you will need to go through the test files.
• Follow the instructions in those files for commenting and uncommenting lines.