README

Models

This problem is about loading Packages onto Trucks and validating that the Truck can hold the Packages.

1. run rails new cargo to create a new Rails app
2. implement a model, Package, with a size attribute
   1. expect Package.create!(size: 10) to create and store an instance of Package
3. implement a model, Truck, that has a capacity attribute and many Packages (a Package may be on a Truck, or it may not)
   1. expect Truck.create!(capacity: 35) to create and store an instance of Truck
   2. expect Package.first.update!(truck: Truck.first) to associate the Package with the Truck
   3. expect Truck.first.packages to return the Package that was added to the Truck
   4. expect Package.create!(size: 5) to create and store an instance of Package
4. add an instance method on Truck called load_cargo that takes a Package and "puts it on the truck"
   1. expect Truck.first.load_cargo(Package.last) to run without error
   2. expect Truck.first.packages to return two Packages, including the Package that was passed to Truck#load_cargo
5. add validation to ensure that the sum of the sizes of its Packages does not exceed a Truck's capacity
   1. expect Package.create!(size: 20) && Truck.first.load_cargo(Package.last) to create and load_cargo a Package
   2. expect Package.create!(size: 1) && Truck.first.load_cargo(Package.last) to create an instance of Package but fail to save the Truck

Controllers

Setup

1. start from the git tag controllers
   1. if you have data in your database, stop the server and run rails db:reset
   2. if you don't have data in your database, run rails db:setup
2. create some model instances

# first Truck
truck = Truck.create!(capacity: 35)
Package.create!(size: 10, truck: truck)
Package.create!(size: 5, truck: truck)
Package.create!(size: 20, truck: truck)

# second Truck
truck = Truck.create!(capacity: 50)
Package.create!(size: 20, truck: truck)
Package.create!(size: 20, truck: truck)
Package.create!(size: 2, truck: truck)

# third Truck
truck = Truck.create!(capacity: 10)

Problems

1. add a Controller for the Truck model, with the actions index and show, and implement a View for the index action that lists the Trucks from the database, showing the attributes id, capacity, and cargo_size for each Truck
   1. expect http://localhost:3000/trucks/index to render the view and show the three Trucks created in the Setup section
2. make each id attribute in the index page a link to the Truck's show page
   1. expect clicking on an id in the index page to take the user to the empty show page
3. implement the show page, to show the same three attributes as the index page
   1. expect the show page to show the attributes
4. on the show page, list the ID of each Package on the Truck
   1. expect the show page to show the ID of each Package on the Truck
5. add a Controller for the Package model, with the show action, and implement a View for Packages#show that displays the Package attributes id and size
   1. expect loading /packages/1 to show the Package with id == 1
6. make each Package id on the Trucks#show page a link to that Package's show page
   1. expect clicking a Package link to take the user to the Package's show page
7. add a JSON response to the Trucks#show action
   1. expect curl -H 'Accept: application/json' http://localhost:3000/trucks/1 to return a JSON hash
8. have the Packages controller return a 403 Forbidden response if the Package ID is odd (i.e. not an even number)
   1. expect /packages/3 to show an error message and not show the package information
   2. expect curl -H 'Accept: application/json' http://localhost:3000/packages/3 to return status code 403 and an error message, and not the package information