Document and test a pattern for app-wide methods (#7)

* Document and test a pattern for app-wide methods

You can do this on `ApplicationRecord`:

```ruby
class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true

  # We're passing specific queues for monitoring, but you may not need or want them.
  performs :touch,   queue_as: "active_record.touch"
  performs :update,  queue_as: "active_record.update"
  performs :destroy, queue_as: "active_record.destroy"
end
```

* Always UTC time so CI is happy?

* Gotta love times on CI

README.md

@@ -99,6 +99,38 @@ class Post < ActiveRecord::Base
 end
 ```
 
+#### Establishing patterns across your app
+
+If there's an Active Record method that you'd like any model to be able to run from a background job, you can set them up in your `ApplicationRecord`:
+
+```ruby
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+
+  # We're passing specific queues for monitoring, but you may not need or want them.
+  performs :touch,   queue_as: "active_record.touch"
+  performs :update,  queue_as: "active_record.update"
+  performs :destroy, queue_as: "active_record.destroy"
+end
+```
+
+Then a model could now run things like:
+
+```ruby
+record.touch_later
+record.touch_later :reminded_at, time: 5.minutes.from_now # Pass supported arguments to `touch`
+
+record.update_later reminded_at: 1.year.ago
+
+# Particularly handy to use on a record with many `dependent: :destroy` associations.
+# Plus if anything fails, the transaction will rollback and the job fails, so you can retry it later!
+record.destroy_later
+```
+
+You may not want this for `touch` and `update`, and maybe you'd rather architect your system in such a way that they don't have so many side-effects, but having the option can be handy!
+
+Also, I haven't tested all the Active Record methods, so please file an issue if you encounter any.
+
 #### Method suffixes
 
 `ActiveJob::Performs` supports Ruby's stylistic method suffixes, i.e. ? and ! respectively.

test/active_job/active_record/test_performs.rb

@@ -2,6 +2,42 @@
 
 module ActiveJob::ActiveRecord; end
 class ActiveJob::ActiveRecord::TestPerforms < ActiveSupport::TestCase
+  setup { @invoice = Invoice.create! }
+
+  test "touch_later" do
+    assert_changes -> { @invoice.reload.updated_at } do
+      assert_performed_with job: ApplicationRecord::TouchJob, args: [@invoice] do
+        @invoice.touch_later
+      end
+    end
+
+    time = Time.now.utc.change(usec: 0)
+    assert_changes -> { @invoice.reload.reminded_at }, to: time do
+      assert_performed_with job: ApplicationRecord::TouchJob, args: [@invoice, :reminded_at, time: time] do
+        @invoice.touch_later :reminded_at, time: time
+      end
+    end
+  end
+
+  test "update_later" do
+    time = Time.now.utc.change(usec: 0)
+    assert_changes -> { @invoice.reload.reminded_at }, to: time do
+      assert_performed_with job: ApplicationRecord::UpdateJob, args: [@invoice, reminded_at: time] do
+        @invoice.update_later reminded_at: time
+      end
+    end
+  end
+
+  test "destroy_later" do
+    assert_enqueued_with job: ApplicationRecord::DestroyJob, args: [@invoice] do
+      @invoice.destroy_later
+    end
+    perform_enqueued_jobs
+    assert_raise(ActiveRecord::RecordNotFound) { @invoice.reload }
+  end
+end
+
+class ActiveJob::ActiveRecord::TestPerformsBulk < ActiveSupport::TestCase
   setup do
     Invoice.insert_all [{}, {}, {}, {}, {}]
   end

test/test_helper.rb

@@ -23,9 +23,17 @@ class ApplicationJob < ActiveJob::Base; end
   end
 end
 
-class Invoice < ActiveRecord::Base
+class ApplicationRecord < ActiveRecord::Base
   include GlobalID::Identification
 
+  self.abstract_class = true
+
+  performs :touch,   queue_as: "active_record.touch"
+  performs :update,  queue_as: "active_record.update"
+  performs :destroy, queue_as: "active_record.destroy"
+end
+
+class Invoice < ApplicationRecord
   performs :deliver_reminder!
   def deliver_reminder!
     touch :reminded_at