Test Rake Tasks

Question

I am developing a ROR app that relies on many custom Rake tasks.

What is the best way to test them?

Answer 1

Rake tasks do need testing, especially if you do some batch processing in it. Testing them is quite easy these days:

class CleanExamsTaskTest < ActiveSupport::TestCase
  def test_deletes_results_of_old_exams
    travel_to Time.zone.parse('2010-07-05 10:00')
    @exam.update!(end: Time.zone.parse('2010-07-04 09:59'))

    assert_difference -> { @exam.answered_questions.count }, -1 do
      capture_io { run_task }
    end
  end

  def test_output
    travel_to Time.zone.parse('2010-07-05 10:00')
    @exam.update!(end: Time.zone.parse('2010-07-04 09:59'))

    assert_output("Exams processed: 1\n") { run_task }
  end

  private

  def run_task
    Rake::Task['exams:clean'].execute
  end
end

Full example

Tested with Ruby >= 1.9 and Rails 5.2. Uses Minitest from stdlib. No other dependencies.