rspec-core

RSpec Core provides the structure for writing executable examples of how your code should behave.

Install

gem install rspec      # for rspec-core, rspec-expectations, rspec-mocks
gem install rspec-core # for rspec-core only

Upgrading from rspec-1.x

See features/Upgrade.md

Get Started

Start with a simple example of behavior you expect from your system. Do this before you write any implementation code:

# in spec/calculator_spec.rb
describe Calculator do
  it "add(x,y) 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
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

See also