Write rspec for rake task - ruby-on-rails

Question

i have task /lib/crawler.rake like that:
namespace :crawler do
area_names = Dir[Rails.root.join("lib", "crawler", "*.rb")].map do |file_name|
File.basename(file_name, ".rb")
end
area_names.each do |area_name|
task area_name.to_sym => :environment do
logger = Logger.new("log/crawl_#{area_name}.log")
# do something
parallel_results = crawler.crawl
mutex = Mutex.new
Parallel.each(parallel_results, in_threads: [parallel_results.count, CRAWL_CONFIG["building_thread_max"]].min) do |pages|
begin
# do something
rescue => e
# do something
raise e
end
end
Availability.update_by_grounds_and_time
end
end
end
Logic here, if everything's ok after parallel, we'll call update_by_grounds_and_time method to update Availability; if get error, we'll stop action and raise error.
So i want to write rspec to test for these cases, i want to mock/stub output of task here (pass or raise error) and check did we call update_by_grounds_and_time method?
Can we don't need invoke really task? can we use Rspec Mock?
Can you help me!
Thank

Answer 1

What I usually do in these cases is I extract the meat into a separate class/service-object/whatever, which is much easier to test. The rake task then becomes just an invoker of that object and, as such, doesn't need to be tested.

Answer 2

If it is defined in Rakefile, try this:
require 'rake'
RSpec.describe "Rake Tasks" do
before do
file, path = Rake.application.find_rakefile_location
Rake.load_rakefile("#{path}/#{file}")
end
it "should invoke some tasks" do
expect(Availability).to receive(:update_by_grounds_and_time)
Rake.application["crawler:#{area_name}"].invoke
end
end
If it is defined in foo.rake, then try this one:
require 'rake'
RSpec.describe "Rake Tasks" do
before do
Rake.application.rake_require('/path/to/lib/tasks/foo')
end
it "should invoke some tasks" do
expect(Availability).to receive(:update_by_grounds_and_time)
Rake.application["crawler:#{area_name}"].invoke
end
end
UPDATE (error case)
For example
# foo.rake
Parallel.each(parallel_results, in_threads: [parallel_results.count, CRAWL_CONFIG["building_thread_max"]].min) do |pages|
begin
foo = Foo.new
foo.bar
# do something else
rescue => e
# do something
raise e
end
end
# foo_spec.rb
require 'rake'
RSpec.describe "Rake Tasks" do
before do
Rake.application.rake_require('/path/to/lib/tasks/foo')
end
it "should not call Availability#update_by_grounds_and_time if error raised" do
allow_any_instance_of(Foo).to receive(:bar).and_raise(StandardError)
expect(Availability).to_not receive(:update_by_grounds_and_time)
expect { Rake.application["crawler:#{area_name}"].invoke }.to raise_error(StandardError)
end
end