README.md

rspec-expectations is used to define expected outcomes.

describe Account do
  it "has a balance of zero when first created" do
    Account.new.balance.should eq(Money.new(0))
  end
end

Basic structure

The basic structure of an rspec expectation is:

actual.should matcher(expected)
actual.should_not matcher(expected)

should and should_not

rspec-expectations adds should and should_not to every object in the system. These methods each accept a matcher as an argument. This allows each matcher to work in a positive or negative mode:

5.should eq(5)
5.should_not eq(4)

What is a matcher?

A Matcher is any object that responds to the following methods:

matches?(actual)
failure_message_for_should

These methods are also part of the matcher protocol, but are optional:

does_not_match?(actual)
failure_message_for_should_not
description

RSpec ships with a number of built-in matchers and a DSL for writing custom matchers.

Issues

The documentation for rspec-expectations is a work in progress. We'll be adding Cucumber features over time, and clarifying existing ones. If you have specific features you'd like to see added, find the existing documentation incomplete or confusing, or, better yet, wish to write a missing Cucumber feature yourself, please submit an issue or a pull request.