Task

My approach

How to use

The challenge is to build a Takeaway app that allows the customer to see a menu (dishes + price) from which she can order a number of items. The customer needs to be able to check the order (price of the dishes + total to pay). The customer will receive a text message indicating the time of delivery. These are the user stories to implement:

As a customer
So that I can check if I want to order something
I would like to see a list of dishes with prices

As a customer
So that I can order the meal I want
I would like to be able to select some number of several available dishes

As a customer
So that I can verify that my order is correct
I would like to check that the total I have been given matches the sum of the various dishes in my order

As a customer
So that I am reassured that my order will be delivered on time
I would like to receive a text such as "Thank you! Your order was placed and will be delivered before 18:52" after I have ordered

Playing around in IRB and using pen and paper, I got a good sense of how the app would be shaped and which objects and messages it would need to contain. From this emerged the Domain Model. Rigidly sticking to the Red/Green/Refactor cycle, one class emerged with accompanying tests. I then refactored the production code, extracting methods to other classes. After making all tests for the new classes pass (stubbing dependencies according to the London School), feature tests helped me integrate the dependencies and to test the functionality of the whole app.

The principles and patterns of design that I drew upon are mainly DRY (Don't Repeat Yourself), SRP (Single Responsibility Principle) and derived from that DI (Dependency Injection). These principles led me to have four classes:

1. Takeaway

2. Order

3. Menu

4. Messager

Text message functionality was integrated using Twilio

Initialize your new restaurant. The standard menu is Italian, but you can pass another menu_name: , which will look for menu's in the lib/menus folder. For example menu_name: :polish will load polish.menu. Please have a look at the default menu for the right formatting.

dalla_mama = Takeaway.new(menu_name: :italian)

Show the menu:

dalla_mama.show_menu

# => Menu

# => Spaghetti Al Pomodoro Fresco E Basilico: £9.50
# => Spaghetti Carbonara: £9.50
# => Spaghetti Alla Bolognese: £8.50
# => Penne All 'Arrabiata: £8.95
# => Fettuccine Al Salmone: £10.95
# => Lasagne Al Forno: £10.50
# => Tagliata Di Manzo Con Rucola: £16.95
# => Scaloppine Melanzane: £15.95

Place an order:

dalla_mama.place_order 'Fettuccine Al Salmone', 3
dalla_mama.place_order 'Lasagne Al Forno', 2

You can see the content of your order so far:

dalla_mama.show_order

# => Fettuccine Al Salmone x3: £32.85
# => Lasagne Al Forno x2: £21.00
# => Total price: £53.85

And to start again:

dalla_mama.reset_order

Once you are satisfied with your order, proceed to checkout passing the exact price as an argument.

dalla_mama.checkout(53.85)

You will get a text confirming your order and estimated delivery time:

# Your order has been confirmed! Expect your yummie food by 20:12
# Fettuccine Al Salmone x3: £32.85
# Lasagne Al Forno x2: £21.00
# Total price: £53.85

Author: Samuel Overloop