A Gentle Introduction to Outside-In Development

Mostly a code driven talk. Code here: https://github.com/timtyrrell/outside_in_development/tree/steps

Transcript

1. A Gentle Introduction to Outside-In Development by: Tim Tyrrell Wednesday, September 25, 13
2. oh hai • Tim Tyrrell • Austinite for almost 4 years • Coming to Austin On Rails for about 4 yrs • I write ruby/rails/javascript • Employed at WellMatch Wednesday, September 25, 13
3. I got this great idea Wednesday, September 25, 13 • “instamanager” to manage my instapaper, otherwise known as “the place where my save articles go to die”
4. Instamanager • rails new instamanager • TDD an InstamanagerService • .... Wednesday, September 25, 13 - Wait, so is this fetch method going to return 10 articles or all of them or what?
5. Wednesday, September 25, 13
6. Focusing on the Wrong Thing Wednesday, September 25, 13
7. What • “Behavior-driven development is an “outside-in” methodology. ” Wednesday, September 25, 13
8. • “It starts at the outside by identifying business outcomes, and then drills down into the feature set that will achieve those outcomes.” Wednesday, September 25, 13
9. Wednesday, September 25, 13 Bustin’ Jeeber
10. • Reversing your perspective, working your way down Wednesday, September 25, 13
11. • You *don’t* start at the service class and work your way out • You *don’t* start by creating your domain/ object model Wednesday, September 25, 13 When you need an object, you add it. It happens “organically”
12. • You don’t write the code until a failing test tells you that you need it Wednesday, September 25, 13 one of the tenets of TDD
13. When? Wednesday, September 25, 13 - Now - Before you write the code - Green-field or brown-field Here is the deal: - Think of it like your “game plan” that actually serves as driving out the features you need and serves as a test framework and documentation
14. Why • You want to deliver the right thing • You are a professional • You don’t want to go off on tangents • You want to go home at night • It is fun! Wednesday, September 25, 13 - Tests stay up to date, docs do not - Gives you documentation
15. How • Write a story • Work your way down the stack Wednesday, September 25, 13
16. Title (one line describing the story) Narrative: As a [role] I want [feature] So that [benefit] Acceptance Criteria: (presented as Scenarios) Scenario 1: Title Given [context] And [some more context]... When [event] Then [outcome] And [another outcome]... Scenario 2: ... Wednesday, September 25, 13 BDD provides the structure of a story Keith Gaddis taught a BDD class and stated “If you can’t fill out the narrative, then you don’t know what you are doing enough to write the code”
17. Wednesday, September 25, 13 - not a “pie in the sky” idea - this works - used by myself at Wellmatch. You would never do this an regret it. Every time ... - used by many other badass shops (Hashrocket, Pivotal, Thoghtbot, Carbon5, etc.) - this is just one way to work, but it does work
18. Tools • Cucumber • RSpec && Shoulda • Jasmine (sorry, cut from the talk #haters) Wednesday, September 25, 13
19. Cucumber • “...serves as documentation, automated tests and development-aid - all rolled into one format.” • Gherkin - plain text DSL • Makes the requests, gets the results, you assert on it Wednesday, September 25, 13 - Cucumber makes the requests and gets the results and you assert on it. This is not a tools talk or a BDD theory talk, but a “flow” talk
20. When /^(?:|I )fill in "([^"]*)" with "([^"]*)"$/ do |field, value| fill_in(field, :with => value) end Wednesday, September 25, 13
21. Let’s Cuke Wednesday, September 25, 13
22. Some Thoughts Wednesday, September 25, 13 - This tests are really too high level to have alone, they are better than nothing but they might hide crap underneath - Good Smoke test - Happy path testing - We usually have the UI done for us already, we just have to go plug it in. So this really is the flow, besides more rspec for business logic. - Generally accepted practice to not test controller. Keep them light,
23. Don’t need Cuke Wednesday, September 25, 13
24. describe "the signin process", :type => :feature do before :each do User.make(:email => 'user@example.com', :password => 'caplin') end it "signs me in" do visit '/sessions/new' within("#session") do fill_in 'Login', :with => 'user@example.com' fill_in 'Password', :with => 'password' end click_link 'Sign in' expect(page).to have_content 'Success' end end Wednesday, September 25, 13 - turnip, spinich, straight selenium
25. WellMatch is Hiring • Sr. Rails Dev • (less Sr.) Rails Dev • Sr. QA • 2 (less Sr.) QA • Great team, WFH, pair-programming • Healthcare Cost-Transparency Software Wednesday, September 25, 13 not some boring ass Accounting software, maybe this will make people’s lives better?
26. Questions? Wednesday, September 25, 13
27. Thanks for listening! • Go forth and write the right code Wednesday, September 25, 13
28. References • http://dannorth.net/whats-in-a-story/ • http://blog.carbonfive.com/2012/02/14/beginning-outside-in-rails- development-with-cucumber-and-rspec/ • http://www.sarahmei.com/blog/2010/05/29/outside-in-bdd/ • http://hashrocket.com/blog/posts/a-case-of-cucumbers Wednesday, September 25, 13