Memoria

Asserts the result of a given test by generating a rendered representation of its output. Inspired by Jest and VCR.

The first time your test is run, a representation of your expected output is saved to a file. The next time you run the same test, a diff runs between a new and the previously stored snapshot. If there are no differences the test passes, otherwise the test fails and the resulting diff is displayed.

Installation

Add this line to your application's Gemfile:

gem 'memoria'

And then execute:

$ bundle

Or install it yourself as:

$ gem install memoria

Usage

RSpec

You can configure RSpec's integration in spec_helper.rb. Require memoria/rspec then run Memoria.configure:

Memoria.configure do |config|
  config.configure_rspec_hooks
  config.include_rspec_matchers
end

The configuration above does two things:

• Includes the matcher match_snapshot in your RSpec test suite.
• Configures RSpec hooks to create snapshots named after the full spec example's description.

Use the provided matcher match_snapshot to verify if the expected output matches a previously recorded snapshot.

expect(view).to match_snapshot

By default the snapshots will be stored in spec/fixtures/snapshots, but you can change this with the setting snapshot_directory:

Memoria.configure do |config|
  config.snapshot_directory = 'spec/snapshots'
end

Cucumber

Under development.

Minitest

Under development.

Development

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.

Architecture

Memoria was designed using a modular plugin architecture. The core part of the gem has a single responsibility: manage snapshots. Every test framework integration is done through a self-contained plugin. Plugins depend on the core, but the core is unaware of the plugins. This allows me to extract the plugins into their own gems later, and add new plugins with ease.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/wilsonsilva/memoria.