-
-
Save graywh/7933217 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
# RSpec matcher to spec delegations. | |
# Forked from https://gist.github.com/ssimeonov/5942729 with fixes | |
# for arity + custom prefix. | |
# | |
# Usage: | |
# | |
# describe Post do | |
# it { should delegate(:name).to(:author).with_prefix } # post.author_name | |
# it { should delegate(:name).to(:author).with_prefix(:any) } # post.any_name | |
# it { should delegate(:month).to(:created_at) } | |
# it { should delegate(:year).to(:created_at) } | |
# it { should delegate(:something).to(:'@instance_var') } | |
# end | |
RSpec::Matchers.define :delegate do |method| | |
match do |delegator| | |
@method = @prefix ? :"#{@prefix}_#{method}" : method | |
@delegator = delegator | |
if @to.to_s[0] == '@' | |
# Delegation to an instance variable | |
old_value = @delegator.instance_variable_get(@to) | |
begin | |
@delegator.instance_variable_set(@to, receiver_double(method)) | |
x = @delegator.send(@method) == :called | |
@delegator.instance_variable_set(@to, nil) | |
if @allow_nil | |
x &= @delegator.send(@method).nil? | |
else | |
begin | |
@delegator.send(@method) | |
x = false | |
rescue NoMethodError => e | |
x &= x.message =~ /for nil:NilClass/ | |
end | |
end | |
x | |
ensure | |
@delegator.instance_variable_set(@to, old_value) | |
end | |
elsif @delegator.respond_to?(@to, true) | |
unless [0,-1].include?(@delegator.method(@to).arity) | |
raise "#{@delegator}'s' #{@to} method does not have zero or -1 arity (it expects parameters)" | |
end | |
@delegator.stub(@to).and_return(receiver_double(method)) | |
x = @delegator.send(@method) == :called | |
@delegator.stub(@to).and_return(nil) | |
if @allow_nil | |
x &= @delegator.send(@method).nil? | |
else | |
begin | |
@delegator.send(@method) | |
x = false | |
rescue NoMethodError => e | |
x &= x.message =~ /for nil:NilClass/ | |
end | |
end | |
x | |
else | |
raise "#{@delegator} does not respond to #{@to}" | |
end | |
end | |
description do | |
"delegate :#{@method} to its #{@to}#{@prefix ? ' with prefix' : ''} and #{@allow_nil ? 'allow nil' : 'throw an error when nil'}" | |
end | |
failure_message_for_should do |text| | |
"expected #{@delegator} to #{description}" | |
end | |
failure_message_for_should_not do |text| | |
"expected #{@delegator} not to #{description}" | |
end | |
chain(:to) { |receiver| @to = receiver } | |
chain(:with_prefix) { |prefix| @prefix = prefix || @to } | |
chain(:allow_nil) { @allow_nil = true } | |
def receiver_double(method) | |
double('receiver').tap do |receiver| | |
receiver.stub(method).and_return(:called) | |
end | |
end | |
end |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment