Rspec is an automated testing framework for Ruby, designed for use in Behaviour Driven Development and Test Driven Development.
rspec-core includes the Rspec runner, output formatters, and the rspec
command.
[sudo] gem install rspec --prerelease
This will install the rspec, rspec-core, rspec-expectations and rspec-mocks gems.
Start with a simple example of behavior you expect from your system. Do this before you write any code:
# in spec/calculator_spec.rb
describe Calculator, "add" do
it "returns the sum of its arguments" do
Calculator.new.add(1, 2).should eq(3)
end
end
Run this with the rspec command, and watch it fail:
$ rspec spec/calculator_spec.rb
./spec/calculator_spec.rb:1: uninitialized constant Calculator
Implement the simplest solution:
# in lib/calculator.rb
class Calculator
def add(a,b)
a + b
end
end
Be sure to require the implementation file in the spec:
# in spec/calculator_spec.rb
# - Rspec adds ./lib to the $LOAD_PATH, so you can
# just require "calculator" directly
require "calculator"
Now run the spec again, and watch it pass:
$ rspec spec/calculator_spec.rb
.
Finished in 0.000315 seconds
1 example, 0 failures
Use the documentation formatter to see the resulting spec:
$ rspec spec/calculator_spec.rb --format doc
Calculator add
returns the sum of its arguments
Finished in 0.000379 seconds
1 example, 0 failures