Behaviour Driven
Development for Ruby.
Development for Ruby.
Making TDD Productive and Fun.
To kick things off, install RSpec and run rspec --init to
set up your project to use RSpec.
Fetching gem metadata from https://rubygems.org/......... Installing diff-lcs 1.2.5 Installing rspec-support 3.1.2 Installing rspec-core 3.1.7 Installing rspec-expectations 3.1.2 Installing rspec-mocks 3.1.3 Installing rspec 3.1.0 Using bundler 1.7.6 Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed. ➜ bowling git:(master) ✗ bin/rspec --init create .rspec create spec/spec_helper.rb ➜ bowling git:(master) ✗ cat .rspec --color --require spec_helper ➜ bowling git:(master) ✗
Start with a very simple example that expresses some basic desired behaviour.
1 require 'bowling'¬ 2 ¬ 3 RSpec.describe Bowling, "#score" do¬ 4 context "with no strikes or spares" do¬ 5 it "sums the pin count for each roll" do¬ 6 bowling = Bowling.new¬ 7 20.times { bowling.hit(4) }¬ 8 expect(bowling.score).to eq 80¬ 9 end¬ 10 end¬ 11 end¬ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ spec/bowling_spec.rb [+] Line:8/11[72%]Col:36Buf:#2[48][0x30]
Run the example and watch it fail.
➜ bowling git:(master) bin/rspec --format doc Bowling#score with no strikes or spares sums the pin count for each roll (FAILED - 1) Failures: 1) Bowling#score with no strikes or spares sums the pin count for each roll Failure/Error: expect(bowling.score).to eq 80 expected: 80 got: nil (compared using ==) # ./spec/bowling_spec.rb:8:in `block (3 levels) in <top (required)>' Finished in 0.00142 seconds (files took 0.13793 seconds to load) 1 example, 1 failure Failed examples: rspec ./spec/bowling_spec.rb:5 # Bowling#score with no strikes or spares sums the pin count for each roll ➜ bowling git:(master)
Implement that basic behaviour...
1 class Bowling¬ 2 attr_reader :score¬ 3 ¬ 4 def initialize¬ 5 @score = 0¬ 6 end¬ 7 ¬ 8 def hit(pin_count)¬ 9 @score += pin_count¬ 10 end¬ 11 end¬ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ lib/bowling.rb Line:10/11[90%]Col:3Buf:#1[101][0x65] "lib/bowling.rb" 11L, 130C written
Run the example and bask in the joy that is green.
➜ bowling git:(master) bin/rspec --format doc Bowling#score with no strikes or spares sums the pin count for each roll Finished in 0.00137 seconds (files took 0.13421 seconds to load) 1 example, 0 failures ➜ bowling git:(master)
Don’t rush ahead with more code. Instead, add another example and let it guide you to what you have to do next. And don’t forget to take time to refactor your code before it gets messy. You should keep your code clean at every step of the way.
This definitive guide from RSpec’s lead developer shows you how to use RSpec to drive more maintainable designs, specify and document expected behavior, and prevent regressions during refactoring. Build a project using RSpec to design, describe, and test the behavior of your code-whether you’re new to testing tools or an experienced developer.
Get the book from The Pragmatic Bookshelf
The Testing Ruby Applications with RSpec screencast introduces the core RSpec libraries through the development of a small CLI card game. In addition to covering the technical aspects of using RSpec, it also covers best practices for using them so you get the most out of your test suite: different types of tests, what kinds of things to test, when different styles are appropriate.
Check out the screencast