ProcMatcher

A matcher for testing proc and lambda equivalance.

Add this line to your application's Gemfile:

gem 'proc_matcher'

And then execute:

$ bundle

Or install it yourself as:

$ gem install proc_matcher

Add this line to your spec_helper.rb file:

include 'proc_matcher'

You will now have access to a matcher called has_same_source_as which allows you to check that procs's have the source code.

require 'spec_helper'

describe 'have_same_source_as' do
  let(:proc1) do
    proc {}
  end

  it 'the same procs should be equal' do
    expect(proc1).to have_same_source_as proc1
  end

  it 'lambdas should not have the same source as procs' do
    expect(proc1).to_not have_same_source_as -> {}
  end

  it 'procs with different parameters only should by default not have the same source' do
    proc1 = proc { |a| a.to_s }

    expect(proc1).to_not have_same_source_as proc { |b| b.to_s }
  end
end

The ignoring_parameter_names allows blocks to be considered to have the same source if they only differ in their parameter names:

require 'spec_helper'

describe 'ignoring_parameter_names' do
  it 'ignoring_parameter_names should allow procs with same effective source but different parameters to have the same source' do
    proc1 = proc { |a| a.to_s }

    expect(proc1).to have_same_source_as(proc { |b| b.to_s }).ignoring_parameter_names
  end
end

Note this matcher depends the sourcify gem to extact the source code. This source extraction only works if:

• the proc is the only proc declared on the same line
• the proc was not created via an eval

• 1.9.3
• 2.0
• 2.1
• 2.2

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/dwhelan/proc_matcher. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.