lib/rspec/expectations.rb



require 'rspec/support'
RSpec::Support.require_rspec_support "caller_filter"
RSpec::Support.require_rspec_support "warnings"
RSpec::Support.require_rspec_support "object_formatter"

require 'rspec/matchers'

RSpec::Support.define_optimized_require_for_rspec(:expectations) { |f| require_relative(f) }

%w[
  expectation_target
  configuration
  fail_with
  handler
  version
].each { |file| RSpec::Support.require_rspec_expectations(file) }

module RSpec
  # RSpec::Expectations provides a simple, readable API to express
  # the expected outcomes in a code example. To express an expected
  # outcome, wrap an object or block in `expect`, call `to` or `to_not`
  # (aliased as `not_to`) and pass it a matcher object:
  #
  #     expect(order.total).to eq(Money.new(5.55, :USD))
  #     expect(list).to include(user)
  #     expect(message).not_to match(/foo/)
  #     expect { do_something }.to raise_error
  #
  # The last form (the block form) is needed to match against ruby constructs
  # that are not objects, but can only be observed when executing a block
  # of code. This includes raising errors, throwing symbols, yielding,
  # and changing values.
  #
  # When `expect(...).to` is invoked with a matcher, it turns around
  # and calls `matcher.matches?(<object wrapped by expect>)`.  For example,
  # in the expression:
  #
  #     expect(order.total).to eq(Money.new(5.55, :USD))
  #
  # ...`eq(Money.new(5.55, :USD))` returns a matcher object, and it results
  # in the equivalent of `eq.matches?(order.total)`. If `matches?` returns
  # `true`, the expectation is met and execution continues. If `false`, then
  # the spec fails with the message returned by `eq.failure_message`.
  #
  # Given the expression:
  #
  #     expect(order.entries).not_to include(entry)
  #
  # ...the `not_to` method (also available as `to_not`) invokes the equivalent of
  # `include.matches?(order.entries)`, but it interprets `false` as success, and
  # `true` as a failure, using the message generated by
  # `include.failure_message_when_negated`.
  #
  # rspec-expectations ships with a standard set of useful matchers, and writing
  # your own matchers is quite simple.
  #
  # See [RSpec::Matchers](../RSpec/Matchers) for more information about the
  # built-in matchers that ship with rspec-expectations, and how to write your
  # own custom matchers.
  module Expectations
    # Exception raised when an expectation fails.
    #
    # @note We subclass Exception so that in a stub implementation if
    # the user sets an expectation, it can't be caught in their
    # code by a bare `rescue`.
    # @api public
    class ExpectationNotMetError < Exception
    end

    # Exception raised from `aggregate_failures` when multiple expectations fail.
    #
    # @note The constant is defined here but the extensive logic of this class
    #   is lazily defined when `FailureAggregator` is autoloaded, since we do
    #   not need to waste time defining that functionality unless
    #   `aggregate_failures` is used.
    class MultipleExpectationsNotMetError < ExpectationNotMetError
    end

    autoload :BlockSnippetExtractor, "rspec/expectations/block_snippet_extractor"
    autoload :FailureAggregator,     "rspec/expectations/failure_aggregator"
  end
end