"Autodelete" to-dos about blocitoff HOT 10 CLOSED

Using Whenever gem, automate the to-do item deletion.

task delete_items: :environment do
  Item.where("created_at <= ?", Time.now - 7.days).destroy_all
end

from blocitoff.

Time.now - 7.days can also be written as 7.days.ago

from blocitoff.

So how do I TDD this? I could write the test in the model specs, but is that where it belongs? Do I create a new file to test the whenever gem? Is there a way to test against the whenever gem? I'm not finding anything easily.

from blocitoff.

Testing rake tasks is tricky. Testing passage of time is also tricky. And it seems you have both problems combined. :)

To test a rake task the best approach is to start with extracing the code into a module. You can put it in app/models and name it like a command (e.g. DeleteItems or DeleteItemsTask). Then the rake code would look like something this:

task delete_items: :environment do
  DeleteItems.run # or "call", or "execute"
end

Testing a module is trivial, you basically test it like any other model.

The second problem: testing passage of time was usually solved using the Timecop gem. But since Rails 4.1 there is now a travel_to testing helper. Use any of those to simulate passage of time in your test.

In the end, a basic test will have the following structure:

1. Make some new todos.
2. Travel in time 7 days into the future.
3. Call the delete-items module.
4. Assert that all todos were removed.

from blocitoff.

So let me make sure I'm understanding this correctly. I can leave my rake task in the lib folder, but also create a app/models/DeleteTodos.rb file, but somehow make this a module? So maybe:

module DeleteTodos
  task delete_todos: :environment do
    Todo.where("created_at <= 7 ?", 1.week.ago).destroy_all
  end
end

Then just write a test in the todo model spec against running this module?

from blocitoff.

I found a few examples online, and thought about trying them. My tests are passing now, but you are my mentor so you can tell me if this is bad practice or something:

require 'rails_helper'
require 'rake'

describe Todo do
  before do
    @user = create(:user)
    @todo = create(:todo, created_at: Time.new(2014, 7, 31, 9, 5, 0))
    load "tasks/delete_todos.rake"
    Rake::Task.define_task(:environment)
  end

  describe "#expiration_date" do
    it "returns the number of days remaining before todo is deleted" do
      expect(@todo.expiration_date).to eq(Time.new(2014, 8, 7, 9, 5, 0))
    end
  end

  describe "#delete_completed_todo" do
    it "deletes the todo after the todo is marked as complete" do
      @todo.update_attribute("completed", true)
      expect(Todo.count).to eq(0)
    end
  end

  describe "#delele_todos" do
    include ActiveSupport::Testing::TimeHelpers
    it "deletes the todo after 7 days" do
      travel_to Time.new(2014, 8, 7, 9, 5, 0) do
        Rake::Task["delete_todos"].invoke
        expect(Todo.count).to eq(0)
      end
    end
  end
end

from blocitoff.

The model file should be named app/models/delete_todos.rb. The convention is to use a camel case for the class names, but snake case for the file names.

Since the rake file is to look like this:

task delete_items: :environment do
  DeleteTodos.run
end

the module file has to look like this:

module DeleteTodos
  def self.run
    Todo.where("created_at <= 7 ?", 1.week.ago).destroy_all
  end
end

from blocitoff.

Loading rake tasks is possible, although I don't like it. I prefer making rake tasks so simple they can't be wrong and then testing the separate modules.

from blocitoff.

Cool:)

Now I understand! I read about it and hear about it, but it's still a foreign idea that people write their own classes and modules in Rails. Seems like Rails just has it all kinda built in for you, so you do not have to write extra things. I guess you have to write a lot of custom stuff in Sinatra!

from blocitoff.

Rails is just a framework, a scaffolding for your code. It does not release you from using good programming practices (like separating business logic into classes and modules in this case).

from blocitoff.