minitest-descriptive

This little plug-in makes your assertion diffs much smarter about the way you write your tests.

Let's say you have this failing test:

class FooTest < MiniTest::Unit::TestCase
  def test_works
    @right = 1
    @wrong = 3
    assert_equal @right, 3
  end
end

Normally Minitest would output this:

1) Failure:
test_works(FooTest) [test_foo.rb:2]:
Expected: 1
  Actual: 3

This is a simple example, but Expected: 1 doesn't give us much information. What did 1 mean? And what is 3??? After 6 months, you've forgotten. But then you look at the test, "oh, 1 was @right and 3 was @wrong! of course".

With minitest-descriptive, your output would be like this:

1) Failure:
test_works(FooTest) [test_foo.rb:2]:
Expected: 1 (@right)
  Actual: 3 (@wrong)

Much more descriptive, isn't it?

If you're running on Rubinius, minitest-descriptive automatically tries to be smart about local variables too. So if we changed the test case to use a local variable:

class FooTest < MiniTest::Unit::TestCase
  def test_works
    @right = 1
    wrong = 3
    assert_equal @right, 3
  end
end

Your output would be like this:

1) Failure:
test_works(FooTest) [test_foo.rb:2]:
Expected: 1 (@right)
  Actual: 3 (wrong)

Cool eh? :)

Add this line to your application's Gemfile:

gem 'minitest-descriptive'

And then execute:

$ bundle

Or install it yourself as:

$ gem install minitest-descriptive

And finally add this to your test_helper.rb file:

require 'minitest-descriptive'

class MiniTest::Unit::TestCase
  include MiniTest::Descriptive
end

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

This was made by Josep M. Bach (Txus) under the MIT license. I'm @txustice on twitter (where you should probably follow me!).