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require 'spec/matchers/extensions/instance_exec'
require 'spec/matchers/pretty'
require 'spec/matchers/matcher'
require 'spec/matchers/operator_matcher'
require 'spec/matchers/be'
require 'spec/matchers/be_close'
require 'spec/matchers/be_instance_of'
require 'spec/matchers/be_kind_of'
require 'spec/matchers/change'
require 'spec/matchers/eql'
require 'spec/matchers/equal'
require 'spec/matchers/errors'
require 'spec/matchers/exist'
require 'spec/matchers/generated_descriptions'
require 'spec/matchers/has'
require 'spec/matchers/have'
require 'spec/matchers/include'
require 'spec/matchers/match'
require 'spec/matchers/match_array'
require 'spec/matchers/method_missing'
require 'spec/matchers/raise_error'
require 'spec/matchers/respond_to'
require 'spec/matchers/satisfy'
require 'spec/matchers/simple_matcher'
require 'spec/matchers/throw_symbol'
require 'spec/matchers/wrap_expectation'
require 'spec/matchers/compatibility'
require 'spec/matchers/dsl'
module Spec
# RSpec ships with a number of useful Expression Matchers. An Expression 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 #optional
#
# These methods are from older versions of the protocol. They are still supported,
# but are not recommended:
#
# failure_message (use failure_message_for_should instead)
# negative_failure_message (use failure_message_for_should_not instead)
#
# See Spec::Expectations to learn how to use these as Expectation Matchers.
#
# == Predicates
#
# In addition to those Expression Matchers that are defined explicitly, RSpec will
# create custom Matchers on the fly for any arbitrary predicate, giving your specs
# a much more natural language feel.
#
# A Ruby predicate is a method that ends with a "?" and returns true or false.
# Common examples are +empty?+, +nil?+, and +instance_of?+.
#
# All you need to do is write +should be_+ followed by the predicate without
# the question mark, and RSpec will figure it out from there. For example:
#
# [].should be_empty => [].empty? #passes
# [].should_not be_empty => [].empty? #fails
#
# In addtion to prefixing the predicate matchers with "be_", you can also use "be_a_"
# and "be_an_", making your specs read much more naturally:
#
# "a string".should be_an_instance_of(String) =>"a string".instance_of?(String) #passes
#
# 3.should be_a_kind_of(Fixnum) => 3.kind_of?(Numeric) #passes
# 3.should be_a_kind_of(Numeric) => 3.kind_of?(Numeric) #passes
# 3.should be_an_instance_of(Fixnum) => 3.instance_of?(Fixnum) #passes
# 3.should_not be_instance_of(Numeric) => 3.instance_of?(Numeric) #fails
#
# RSpec will also create custom matchers for predicates like +has_key?+. To
# use this feature, just state that the object should have_key(:key) and RSpec will
# call has_key?(:key) on the target. For example:
#
# {:a => "A"}.should have_key(:a) => {:a => "A"}.has_key?(:a) #passes
# {:a => "A"}.should have_key(:b) => {:a => "A"}.has_key?(:b) #fails
#
# You can use this feature to invoke any predicate that begins with "has_", whether it is
# part of the Ruby libraries (like +Hash#has_key?+) or a method you wrote on your own class.
#
# == Custom Matchers
#
# When you find that none of the stock Expectation Matchers provide a natural
# feeling expectation, you can very easily write your own using RSpec's matcher
# DSL or writing one from scratch.
#
# === Matcher DSL
#
# Imagine that you are writing a game in which players can be in various
# zones on a virtual board. To specify that bob should be in zone 4, you
# could say:
#
# bob.current_zone.should eql(Zone.new("4"))
#
# But you might find it more expressive to say:
#
# bob.should be_in_zone("4")
#
# and/or
#
# bob.should_not be_in_zone("3")
#
# You can create such a matcher like so:
#
# Spec::Matchers.create :be_in_zone do |zone|
# match do |player|
# player.in_zone?(zone)
# end
# end
#
# This will generate a be_in_zone method that returns a matcher
# with logical default messages for failures. You can override the failure
# messages and the generated description as follows:
#
# Spec::Matchers.create :be_in_zone do |zone|
# match do |player|
# player.in_zone?(zone)
# end
# failure_message_for_should do |player|
# # generate and return the appropriate string.
# end
# failure_message_for_should_not do |player|
# # generate and return the appropriate string.
# end
# description do
# # generate and return the appropriate string.
# end
# end
#
# Each of the message-generation methods has access to the block arguments
# passed to the create method (in this case, zone). The
# failure message methods (failure_message_for_should and
# failure_message_for_should_not) are passed the actual value (the
# receiver of should or should_not).
#
# === Custom Matcher from scratch
#
# You could also write a custom matcher from scratch, as follows:
#
# class BeInZone
# def initialize(expected)
# @expected = expected
# end
# def matches?(target)
# @target = target
# @target.current_zone.eql?(Zone.new(@expected))
# end
# def failure_message_for_should
# "expected #{@target.inspect} to be in Zone #{@expected}"
# end
# def failure_message_for_should_not
# "expected #{@target.inspect} not to be in Zone #{@expected}"
# end
# end
#
# ... and a method like this:
#
# def be_in_zone(expected)
# BeInZone.new(expected)
# end
#
# And then expose the method to your specs. This is normally done
# by including the method and the class in a module, which is then
# included in your spec:
#
# module CustomGameMatchers
# class BeInZone
# ...
# end
#
# def be_in_zone(expected)
# ...
# end
# end
#
# describe "Player behaviour" do
# include CustomGameMatchers
# ...
# end
#
# or you can include in globally in a spec_helper.rb file required
# from your spec file(s):
#
# Spec::Runner.configure do |config|
# config.include(CustomGameMatchers)
# end
#
module Matchers; end
end© 2015 - 2025 Weber Informatics LLC | Privacy Policy