A small gem to lubricate your testing workflow with prettier than usual diffs.

When you make assertions between large strings with Minitest, for example JSON responses, it is laborious to identify what has changed. The usual workflow involves copy-pasting the output into a diff tool; a rather boring and time-consuming process.

Minitest chooses to compare strings using diff, which is line-oriented. However, 99% of the time, we do not intend to compare lines, we want just the words.

PrettyDiffs is a tool that supports this desire by overriding the default Minitest method, and relieves our workflow.

Wdiff is a wrapper around diff, it works by creating two temporary files, one word per line, and then executes diff on these files. It collects the diff output and uses it to produce a nicer display of word differences between the original files.

# mac
$ brew install wdiff 

# linux
$ apt get-install wdiff 

Add this line to your application's Gemfile:

group :test do
  gem 'pretty-diffs'
end

And then execute:

$ bundle

Or install it yourself as:

$ gem install pretty-diffs

Include the module in the Minitest classes to trigger the pretty diffs:

require 'pretty_diffs'

module ActiveSupport

  class TestCase
    include PrettyDiffs # add this line

  end
end

In this rare case, set the following ENV variable:

MINITEST_PLAIN_BORING_DIFF='yes'

$ rake

• Pure JSON output instead of Hash when comparing JSON responses in controller tests, so to copy-paste directly.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

The MIT License (MIT)

Copyright (c) 2016 Angelos Karagkiozidis

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.