delayed_job_test_unit.rb

job = Delayed::Job.last
assert_equal(Delayed::PerformableMethod, job.payload_object.class)
assert_equal("AR:User:#{@user.id}", job.payload_object.object)
assert_equal(:my_method, job.payload_object.method)
assert_equal([1,2,3], job.payload_object.args)

invoke_job.rb

should "execute Delayed::Job task" do
  job = Delayed::Job.last
  assert job.invoke_job # if succefully return true
end