How would I rspec/test an updated_at field without using sleep() in ruby?

Question

How do i write my spec without using the sleep(1.second) method? When I remove the sleep then my tests break because they are returning the same time stamp?

I have the following class method:

def skip
qs = find_or_create_by(user_id: user_id)
qs.set_updated_at
qs.n_skip += 1
qs.save!
end

and following spec:

    qs = skip(user.id)
    sleep(1.second)
    qs2 = skip(user.id)
    qs.should_not be_nil
    qs2.should_not be_nil
    (qs.updated_at < qs2.updated_at).should be_true

Answer 1

I've used the Timecop gem in the past for doing time based testing.

require 'timecop'
require 'test/unit'

class MyTestCase < Test::Unit::TestCase
  def test_mortgage_due_in_30_days
    john = User.find(1)
    john.sign_mortgage!
    assert !john.mortgage_payment_due?
    Timecop.travel(Time.now + 30.days) do
      assert john.mortgage_payment_due?
    end
  end
end

So your example may look like:

qs = skip(user.id)

Timecop.travel(Time.now + 1.minute) do
  qs2 = skip(user.id)
end

qs.should_not be_nil
qs2.should_not be_nil
(qs.updated_at < qs2.updated_at).should be_true

Answer 2

This also works well for rspec tests. In your Gemfile:

require 'timecop', group: :test

Then, for example, you can use rspec to test a named scope that gets model called queries in descending updated_at order:

require 'timecop'
require 'spec_helper'

describe Query do

  # test the named scopes for ordering and searching
  describe 'when a query is searched or sorted' do

    before :each do
      @query1 = create(:query)
      Timecop.travel(Time.now + 1.minute) do
        @query2 = create(:query)
      end
      Timecop.travel(Time.now + 2.minute) do
        @query3 = create(:query)
      end
    end

    it 'should be listed in descending updated_at order' do
      @queries = Query.order_by_latest
      @queries.first.should == @query3
      @queries.last.should == @query1
    end

  end
end