1. WTF is TDD
A journey to writing awesome code, one test at a time
2. WTF we'll be covering
● What is testing, Why test, and How testing
will make you a better person
● What is TDD, why do it, and why it's better
than writing tests AFTER you've written
your code
● Go over a code example built out with TDD
3. Who TF is this guy?
● Steven Nunez (@_StevenNunez)
○ Junior Developer at Cyrus Innovation
■ AWESOME PLACE! Premier Dev Shop
● Agile/TDD All day, E'ryday
○ Organizer of Unearth Ruby
■ http://www.meetup.com/unearthruby/
○ Co-Organizer of NYC Rubyist Roundtable
■ http://www.meetup.com/nycruby/
4. Stuff you need to F'ing know
How to read this:
class Order
attr_reader :items
def initialize
@items = Hash.new(0)
end
def add(item)
items[item] += 1
end
end
5. What Is Testing
The Act of isolating parts of your code with a
known state to ensure it works as expected.
Setup follows AAA principle:
Arrange - Put your code in some state
Act - Cause its state to change (or not)
Assert - Verify your getting what you expect
6. Types of testing
● End to end tests/ Acceptance tests
○ Here there be Cucumbers. Capybara, Webrat
○ Used to ensure system works as a whole
● Unit Tests
○ Rspec, Test::Unit, Minitest
○ View tests
○ Controller tests
○ Model tests
We'll be covering Unit Tests
7. Why Test
● Lets you know when things break
○ You'd be surprised how code works (or doesn't)
● Allows for courageous refactoring
● Gives documentation on how your code is
SUPPOSED to work. Learn to expect tests.
● It is your duty to deliver working code. The
only way to ensure you've done your job is
for it to be verified somehow.
8. Testing basics
We'll be using Rspec...
http://rspec.info/
https://github.com/rspec/rspec-
expectations#built-in-matchers
Codey Code! ----> http://bit.ly/PUwQLf
10. Why do TDD?
● Forces you to think small
○ You have a clear objective
● Less thoughts to juggle
○ All you know is how you want it to work
● Leads to modular code
○ Each part of your code does one job
● Write less code
● Increase documentation
● It makes you happy!
○ Red, Green, REFACTOR!
http://edu.mkrecny.com/thoughts/be-nice-to-programmers
11. How to TDD
Red Green Refactor
1. Write a test.
2. Watch it fail.
3. Write code to pass your test.
4. Look for ways to make your code more
expressive
5. GOTO 1
12. Our task
Avi, in his infinite wisdom has figured that this tech bubble is about to burst and really wants to
prepare us for a long healthy life in Fast Food. His newest venture: Avi's Ovulating Avians, is a
boutique breakfast shop that plans to disrupt the food consumption market in a big way.
He wants to leverage our algorithm wrangling skills to write a food matching meal recommendation
engine to make upselling our products to our unsuspecting patrons easier.
What do we need for version 0.1?
We need a way to capture customer orders, and inspect the order's ingredients. We'll then need to
make recommendations based on those ingredients.
Things we're building
A Menu with Menu Items in it.
The Items need to have a name, price, calorie count, and ingredients
Orders consist of a menu item, and a quantity.
Orders can calculate their total
Recommender can recommend Menu Items based on the ingredients in a menu item.
https://github.com/StevenNunez/FlatironDiner
