Clockwork::Test

Clockwork is a scheduler process for running scheduled jobs. These scheduled jobs are likely of critical importance to your application. You need to ensure that the jobs run when they should, as often as they should, and with the proper behavior when run.

Clockwork::Test includes additional functionality that makes testing of your clock.rb file easy. This gem can help make sure that you have scheduled your events appropriately, including testing if: or at: conditions, as well as allowing you to run assertions against the code that is executed when a job is run.

Clockwork::Test has been verified against the latest release of clockwork at the time of its development, which is version 1.2.0. It does not require any specific test framework to be used with it, though all examples will use rspec.

Installation

Add this to your application's Gemfile:

group :test do
  gem 'clockwork-test'
end

And then execute:

$ bundle

Or install it yourself as:

$ gem install clockwork-test

Example Tests

Given the following clock.rb file:

require "clockwork"

module Clockwork
  configure do |config|
    config[:tz] = "US/Eastern"
  end

  handler { |job| logger.info "Running #{job}" }

  every(1.minute, "Run a job") do
    "Here's a running job"
  end
end

The following tests may be run against it:

describe Clockwork do
  after(:each) { Clockwork::Test.clear! }

  it "runs the job once" do
    Clockwork::Test.run(max_ticks: 1)

    expect(Clockwork::Test.ran_job?("Run a job")).to be_truthy
    expect(Clockwork::Test.times_run("Run a job")).to eq 1
    expect(Clockwork::Test.block_for("Run a job").call).to eq "Here's a running job"
  end

  it "runs the job every minute over the course of an hour" do
    start_time = Time.new(2015, 11, 2, 2, 0, 0)
    end_time = Time.new(2015, 11, 2, 3, 0, 0)

    Clockwork::Test.run(start_time: start_time, end_time: end_time, tick_speed:
1.minute)

    expect(Clockwork::Test.times_run("Run a job").to eq 60
  end

  describe "RSpec Custom Matcher" do
    subject(:clockwork) { Clockwork::Test }

    before { Clockwork::Test.run(max_ticks: 1) }

    it { should have_run("Run a job") }
    it { should have_run("Run a job").once }

    it { should_not have_run("Run a job").exactly(2).times }
  end
end

Usage

Replacing any calls to Clockwork with Clockwork::Test in your tests should perform as expected, with the one caveat that a job running in Clockwork::Test will not actually execute its event's handler code. That is suppressed, but made available via the block_for method.

Running Clockwork in Tests

A call to Clockwork.run will run the clockwork process until it is signaled to stop, such as by receiving the SIGINT signal. Clockwork::Test.run provides two ways to easily stop the current execution:

After a particular number of clock ticks (See the max_ticks configuration setting).
After a moment in time has been reached (See the end_time configuration setting).

Either of these methods can be used by passing the proper configuration option into the run method of Clockwork::Test. If both are provided, whichever occurs first will be used to halt execution.

Configuration Settings

max_ticks

Setting the max_ticks will determine the number of times that clockwork will run any events scheduled at that time. This is commonly used to let clockwork execute once, to then see if particular jobs are triggered right when clockwork starts up.

start_time

This is the time that you would like the clock file to start processing it. This may be used with either the max_ticks or end_time option to halt execution of the run loop.

If the start_time option is used, Time.now will be modified to the start_time at the beginning of execution of Clockwork::Test.run, and will be returned to the proper time at the conclusion of the run.

end_time

This specifies the time at which execution of clockwork should terminate. The run loop will continue until the end_time is reached, provided the max_ticks has not been exceeded, if that is provided.

This is commonly used along with start_time and tick_speed to quickly see if jobs run as often as expected over a certain period of time.

tick_speed

tick_speed should be provided as a unit of time, such as 1.minute or 3.hours. It is the amount of time that the test will progress time to on every subsequent clock tick.

If tick_speed is set to 1.minute and the current time is 13:00, the first tick will occur at 13:00, and the second will appear occur at 13:01.

This can be used in concert with start_time and end_time to quickly simulate moving across a large period of time, without having to wait for the full time period to occur in reality.

Note that tick_speed should not be set any higher than the minimum amount of granularity used in the clock file under test. Should the tick_speed be set to a higher amount, the number of times a job is run, or if the job is run at all, is subject to inconsistent and inaccurate results.

For example, with a tick_speed of 30.minutes and a job that runs every 1.minute over the course of an hour, the times_ran for that job will not be 60. It will be 2, assuming minimal passage of time in evaluating the actual clock tick.

file

The location of the clock file to test. This defaults to "./config/clock.rb" if a value is not provided.

Assertions Against Test Runs

After running your clock file with Clockwork::Test.run, you can use the following methods to assert the clock file ran as expected:

ran_job?

ran_job? lets you know if a particular job ran during previous executions of Clockwork::Test.run.

If the job "test_job" has run, ran_job?("test_job") will be true; otherwise, the method will return false.

times_run

times_run provides the number of times a job has run during previous executions of Clockwork::Test.run.

If the job "test_job" never ran, times_run("test_job") will be 0; otherwise, it will be the number of times that the event was executed.

block_for

block_for returns the block that would be handled and run on each execution of a job. This can be useful for ensuring that the block you associated with an event does whatever it is that you expect it to do.

If the job "test_job" never ran, block_for("test_job") will return an empty proc; otherwise, the block of code that the event would run is returned, which can then be called to test.

RSpec Matchers

Clockwork::Test includes a rspec test matcher to check if a job has been run.

To use, add the following to your spec_helper.rb:

RSpec.configure do |config|
  config.include(Clockwork::Test::RSpec::Matchers)
end

The have_run matcher checks if a job by the name provided has been run, and allows for a specific number of times to be checked against.

expect(Clockwork::Test).to have_run("Job Name").exactly(42).times

You can alternatively pass the number of times in as an optional argument in the have_run method, as such:

expect(Clockwork::Test).to have_run("Job Name", times: 42)

Chaining once to have_run will check that the job was run one time only.

If you do not pass the number of times, either with a chained method call or as an optional argument to have_run, the matcher will just check if the job was run at all. It provides no assertion as to how often it was run, just that it's at least once.

Resetting the clock

After each invocation of Clockwork::Test.run and assertions made against it, Clockwork::Test.clear! should be called. This will wipe all history away and load up the clock file fresh on the next run. Failure to do so across tests will carry over past history, which will cause the number of times a job has run to be incorrect and subject to a test ordering bug.

Contributing

Fork it ( https://github.com/kevin-j-m/clockwork-test/fork )
Create your feature branch (git checkout -b my-new-feature)
Run the tests (rspec) and ensure they pass
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request
Add a new entry to the CHANGELOG.md in the Current Release section. Include a description of the change, the PR, and your name.

aprescott / clockwork-test