The document provides best practices for writing tests using RSpec for Ruby code. It recommends that tests support object-oriented principles, serve as technical documentation, and focus on describing classes, methods, and edge cases using contexts and examples. The document demonstrates setting up RSpec tests with descriptive blocks, prefixes, and matchers to validate outputs in a clear and maintainable way while following test-driven development principles.

1. Applying RSpec
Best Practices
Kevin McKelvin
Rubyfuza 2013

2. Ground Rules
• Tests must support OO principles
• Tests must be technical documentation
for the code

3. The Example
Conway’s Game of Life
Deterministic
Zero Player Game

4. Be descriptive
it “should work!” do
end

5. The describe block
describe Game do
end
Describe a Ruby Constant

6. The describe block
describe Game do
describe "#tick" do
end
end
Prefix instance methods with #
and class methods with .

7. The context block
describe Game do
describe "#tick" do
context "when given an empty world" do
end
end
end
Use contexts to find edge cases
Start contexts with when or with

8. The it block
describe Game do
describe "#tick" do
context "when given an empty world" do
it "returns an empty world" do
end
end
end
end
“Do or do not, there is no try” -
Yoda

9. Use RSpec Matchers
describe Game do
describe "#tick" do
context "when given an empty world" do
it "returns an empty world" do
empty_world = World.new
second_world = subject.tick(
empty_world)
second_world.empty?.must.equal true
end
end
end
end

10. Use RSpec Matchers
describe Game do
describe "#tick" do
context "when given an empty world" do
it "returns an empty world" do
empty_world = World.new
second_world = subject.tick(
empty_world)
second_world.must.be_empty
end
end
end
end

11. RSpec Settings
.rspec
--color --profile --format d

12. Running Your Specs
Game
#tick
when given an empty world
returns an empty world
when given a world with one cell
returns an empty world
when given a world with three adjacent
cells
returns a world with one cell

13. Remember TDD
Support Object Oriented best-practices
SOLID
Law of Demeter

14. Remember TDD
Don’t test your framework

15. Remember TDD
Avoid integration testing where possible

16. Remember TDD
Be the first consumer of your public API

17. Resources
RSpec:
http://rspec.info/
The RSpec Book:
http://pragprog.com/book/achbd/the-rspec-book
Better Specs:
http://www.betterspecs.org
Mustard:
https://github.com/ryanb/mustard