⌚️ Timecop::Rspec

Timecop::Rspec provides Timecop time-machines for RSpec that allow you to time-travel test examples, context/describes, and/or your entire test suite.

The gem was never released by its original author, who later moved on to work in other languages. Zach Taylor did a great job with it, and people have been hoping it would be published. It has a great API, and I was about to build this exact thing myself, so I am glad I found this. I've modernized everything, added more tests and documentation, and released it. Thanks to the long-term stability of both RSpec and Timecop, the original code still works perfectly.

Improvements over original:

• The original only supported Ruby 2.2+, but I've backfilled support to 1.9.2 (to align with the max-min version between RSpec & Timecop).
• Added tests for 100% line coverage.
• Added documentation for all public methods.
• removed runtime (and dev) dependency on activesupport.

I expect the current release of this gem to be compatible with Ruby 1.9.2+, but it is only tested on CI against Ruby 2.3+, due to the inherent limitations of GitHub Actions.

I have only found one, but it didn't have the API I wanted.

• rspec-timecop - A very different approach

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Install the gem and add to the application's Gemfile by executing:

$ bundle add timecop-rspec

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install timecop-rspec

This gem is cryptographically signed, and has verifiable SHA-256 and SHA-512 checksums by stone_checksums. Be sure the gem you install hasn’t been tampered with by following the instructions below.

Add my public key (if you haven’t already, expires 2045-04-29) as a trusted certificate:

gem cert --add <(curl -Ls https://raw.github.com/galtzo-floss/certs/main/pboling.pem)

You only need to do that once. Then proceed to install with:

gem install timecop-rspec -P HighSecurity

The HighSecurity trust profile will verify signed gems, and not allow the installation of unsigned dependencies.

If you want to up your security game full-time:

bundle config set --global trust-policy MediumSecurity

MediumSecurity instead of HighSecurity is necessary if not all the gems you use are signed.

NOTE: Be prepared to track down certs for signed gems and add them the same way you added mine.

# spec_helper.rb or some configuration file loaded by spec_helper.rb

require "timecop/rspec"

RSpec.configure do |config|
  config.around(:example) do |example|
    Timecop::Rspec.time_machine.run(example)
  end
end

The regular time machine will run each example at the time specified by the RSpec metadata, or the global travel time.

# spec_helper.rb or some configuration file loaded by spec_helper.rb

require "timecop/rspec"

RSpec.configure do |config|
  config.around(:example) do |example|
    Timecop::Rspec.time_machine(:sequential => true).run(example)
  end
end

The sequential time machine is almost the same as the regular time machine, except that it will sometimes resume time travel.

Global travel will always resume from when the previous global traveled example ended. E.g.

# GLOBAL_TIME_TRAVEL_TIME=2014-11-15 bundle exec rspec some_spec.rb

it "example 1" do
  Time.now # => 2014-11-15 00:00:00
  sleep 6
end

it "example 2" do
  Time.now # => 2014-11-15 00:00:06 (resumed from end of previous example)
end

Following local travel will resume when specified time is the same as the previous examples specified time. If the time is different, it will start from the current examples specified time.

describe SomeUnit, :travel => Time.new(2014, 11, 15) do
  it "example 1" do
    Time.now # => 2014-11-15 00:00:00
    sleep 6
  end

  it "example 2" do
    Time.now # => 2014-11-15 00:00:06 (resumed from end of previous example)
  end

  it "example 3", :travel => Time.new(1982, 6, 16) do
    Time.now # => 1982-06-16 00:00:00
  end
end

Timecop.travel/freeze any RSpec (describe|context|example) with :travel or :freeze metadata.

# Timecop.travel
it "some description", :travel => Time.new(2014, 11, 15) do
  Time.now # 2014-11-15 00:00:00
  sleep 6
  Time.now # 2014-11-15 00:00:06 (6 seconds later)
end

# Timecop.freeze
it "some description", :freeze => Time.new(2014, 11, 15) do
  Time.now # 2014-11-15 00:00:00
  sleep 6
  Time.now # 2014-11-15 00:00:00 (Ruby's time hasn't advanced)
end

Using global time travel will Timecop.travel any example that isn't already time traveling. I.e. example level timecop metadata will take precedence.

GLOBAL_TIME_TRAVEL_TIME=2014-11-15 bundle exec rspec spec/some_directory/

The global time travel can also be skipped. You may want to skip time travel when testing with some external service, such as redis, where you can't modify time the same way as within ruby.

it "some example that can't time travel", :skip_global_travel do
  # Time.now will be real time
end

How wonderful it is that nobody need wait a single moment before starting to improve the world.
—Anne Frank

I’m driven by a passion to foster a thriving open-source community – a space where people can tackle complex problems, no matter how small. Revitalizing libraries that have fallen into disrepair, and building new libraries focused on solving real-world challenges, are my passions — totaling 79 hours of FLOSS coding over just the past seven days, a pretty regular week for me. I was recently affected by layoffs, and the tech jobs market is unwelcoming. I’m reaching out here because your support would significantly aid my efforts to provide for my family, and my farm (11 🐔 chickens, 2 🐶 dogs, 3 🐰 rabbits, 8 🐈‍ cats).

If you work at a company that uses my work, please encourage them to support me as a corporate sponsor. My work on gems you use might show up in bundle fund.

I’m developing a new library, floss_funding, designed to empower open-source developers like myself to get paid for the work we do, in a sustainable way. Please give it a look.

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See SECURITY.md.

If you need some ideas of where to help, you could work on adding more code coverage, or if it is already 💯 (see below) check reek, issues, or PRs, or use the gem and think about how it could be better.

We so if you make changes, remember to update it.

See CONTRIBUTING.md for more detailed instructions.

See CONTRIBUTING.md.

Everyone interacting with this project's codebases, issue trackers, chat rooms and mailing lists agrees to follow the .

Made with contributors-img.

Also see GitLab Contributors: https://gitlab.com/galtzo-floss/timecop-rspec/-/graphs/main

This Library adheres to . Violations of this scheme should be reported as bugs. Specifically, if a minor or patch version is released that breaks backward compatibility, a new version should be immediately released that restores compatibility. Breaking changes to the public API will only be introduced with new major versions.

dropping support for a platform is both obviously and objectively a breaking change
—Jordan Harband (@ljharb, maintainer of SemVer) in SemVer issue 716

I understand that policy doesn't work universally ("exceptions to every rule!"), but it is the policy here. As such, in many cases it is good to specify a dependency on this library using the Pessimistic Version Constraint with two digits of precision.

For example:

spec.add_dependency("timecop-rspec", "~> 1.0")

SemVer should, but doesn't explicitly, say that dropping support for specific Platforms is a breaking change to an API. It is obvious to many, but not all, and since the spec is silent, the bike shedding is endless.

To get a better understanding of how SemVer is intended to work over a project's lifetime, read this article from the creator of SemVer:

• "Major Version Numbers are Not Sacred"

See CHANGELOG.md for a list of releases.

The gem is available as open source under the terms of the MIT License . See LICENSE.txt for the official Copyright Notice.

• Copyright (c) 2025 Peter H. Boling, of Galtzo.com , and timecop-rspec contributors.
• Copyright (c) 2014-2017 Zach Taylor & Avant

P.S. If you need help️ or want to say thanks, 👇 Join the Discord.