So now you’re integration testing, because that’s what cool kids are doing these days. This tests the joints of your app, making sure that the model code is being called from the controller code which is being invoked by the user.
A good integration test, as we all know, is from the user’s perspective: “I click this”, “I fill in that”, etc.
But what of rake tasks? Those are integration points. If they go wrong you’re depending on cron telling you, or maybe it’s a task you run once a year by hand. Either way, you want to test it.
We already move all of the rake task into the model. This simplifies unit testing; rake tasks are now just one method call, and that method is isolation tested.
Here’s an integration test for a rake task that sends an email with all new users:
require 'test_helper'
class DailyEmailReportTest < ActionController::IntegrationTest
# In order to keep updated, I should see an email
# of all new users' profile in the past day
should "send an email from the rake test for the specific task" do
old_user = Factory(:user,
:created_at => 2.days.ago,
:description => "old description")
new_user = Factory(:user,
:created_at => 1.hour.ago,
:description => "new description")
ActionMailer::Base.deliveries.clear
i_call_rake_task "notifications:daily:users"
i_see_in_email "new description"
i_do_not_see_in_email "old description"
end
end
Two test helpers are defined to help out: #i_see_in_email and
#i_do_not_see_in_email. In addition to those (they just look over
ActionMailer::Base.deliveries), we have #i_call_rake_task. That’s where the
magic happens.
The first step is to override Rake::Task#invoke_prerequisites to avoid
reloading the environment:
require 'rake'
# Do not re-load the environment task
class Rake::Task
def invoke_prerequisites(task_args, invocation_chain)
@prerequisites.reject{|n| n == "environment"}.each do |n|
prereq = application[n, @scope]
prereq_args = task_args.new_scope(prereq.arg_names)
prereq.invoke_with_call_chain(prereq_args, invocation_chain)
end
end
end
Then we define the helper:
class Test::Unit::TestCase
def i_call_rake_task(task_name)
# Make sure you're in the RAILS_ROOT
oldpwd = Dir.pwd
Dir.chdir(RAILS_ROOT)
# Get an instance of rake
rake_app = Rake.application
rake_app.options.silent = true
# Back to where you were
Dir.chdir(oldpwd)
rake_app.init
rake_app.load_rakefile
task = rake_app.tasks.detect {|t| t.name == task_name}
assert_not_nil task, "No rake task defined: #{task_name}"
task.reenable
task.invoke
end
end
With this in place, you can be more sure that rake tasks are integrated with your system. Wee!
