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Test your Rake tasks in RSpec more easily
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Gem Version Build Status

Makes it easy to test your Rake tasks with RSpec. Read this for more.


Add this line to your application's Gemfile:

gem "fantaskspec"

And then execute:

$ bundle install

Then in your spec_helper or rails_helper:

require "fantaskspec"

RSpec.configure do |config|
  # ...
  # ...

That will make it so that specs in spec/lib/tasks and spec/tasks will automatically have a type of :rake (unless you override it). If you don't want to use infer_rake_task_specs_from_file_location! you can explicitly set the spec type like so:

RSpec.describe "namespace:foo", type: :rake do
  # Lots of lovely specs

Loading your Rake tasks

This gem doesn't load your Rake tasks for you, that's something you have to do. If you're using Rails, just add Rails.application.load_tasks to your rails_helper.rb. If you're not using Rails, just require the files you need.


Given a task that looks like this:

desc "Some rake task"
task some_task: :environment do
  puts "I don't do much."

We can test it like this:

require "spec_helper"

RSpec.describe "namespace:taskname", type: :rake do
  it { depend_on(:environment) }

  it "executes some code" do
    expect(subject.execute).to eq(task.execute)

  context "some sort of context" do
    it "still uses 'some_task' as the name of the task" do
      expect(task_name).to eq("some_task")
      expect(task_name).to eq(

Here subject and task are both the Rake task some_task. Fantaskspec also gives us the handy depend_on matcher so we can ensure our dependencies are correct.

If you only care about some of your task's dependencies you can use depend_on_subset instead of depend_on.

Here we're assuming we've called config.infer_rake_task_specs_from_file_location! in our RSpec.configure block so we don't need to specify type: :rake in any of our example groups as long as the test is located at spec/tasks or spec/lib/tasks.

We also have access to task_name, which is just the Fantaskspec's best guess at the name of the task we're specifying is, based on the description string we pass to describe or context.


If your task requires arguments, just use the to_task_arguments helper.

arguments = to_task_arguments("foo", "bar")

Rake testing gotchas

There are 2 ways to get your Rake task's code to execute: by calling either execute or invoke on the task (or subject). execute will execute the Rake task but none of its dependencies. invoke will execute the task and dependencies, but the task and its dependencies will be disabled unless you call reenable on all of them. If you stick with `execute you probaly won't have any problems.


  1. Fork it
  2. Clone it locally
  3. cd into the project root
  4. bundle install
  5. appraisal install
  6. Run the specs with appraisal rspec
  7. Create your feature branch (git checkout -b my-new-feature)
  8. Commit your changes (git commit -am 'Add some feature')
  9. Push to the branch (git push origin my-new-feature)
  10. Create a new Pull Request
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