GroundhogDay

Monkey patches Date, Time, and DateTime to replay a day over, and over, and over. Original use case: Fork a production database, run a long task on a certain day. Make some changes, run the same long task on the same day.

Add this line to your application's Gemfile:

gem 'groundhog_day'

And then execute:

$ bundle

Or install it yourself as:

$ gem install groundhog_day

Today will always be the date provided.

Date.today # => 2016-02-02

GroundhogDay.enable! date: Date.new(2014, 11, 15)

Date.today # => 2014-11-15

# ... wait for a day to pass
Date.today # => 2014-11-15

GroundhogDay.disable!

Date.today # => 2016-02-03

Now will always be the date provided, but time will be real-time.

Time.now # => 2016-02-02 10:00:00 -0600

GroundhogDay.enable! date: Date.new(2014, 11, 15)

Time.now # => 2014-11-15 10:00:05 -0600

# ... wait 10 minutes
Time.now # => 2014-11-15 10:10:05 -0600

GroundhogDay.disable!

Time.now # => 2016-01-29 10:10:10 -0600

# config/initializers/groundhog_day.rb

if (groundhog_date = ENV['GROUNDHOG_DATE'])
  require 'groundhog_day'
  GroundhogDay.enable! date: Date.parse(groundhog_date)
end

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/taylorzr/groundhog_day.

The gem is available as open source under the terms of the MIT License.