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Hooks: Before and After

caution

Knapsack Pro hooks are only available in Queue Mode.

Knapsack exposes four hooks to execute arbitrary code before or after certain events:

KnapsackPro::Hooks::Queue.before_queue do |queue_id|
  puts 'before_queue - run before the test suite'
end

KnapsackPro::Hooks::Queue.before_subset_queue do |queue_id, subset_queue_id|
  puts 'before_subset_queue - run before the next subset of tests'
end

KnapsackPro::Hooks::Queue.after_subset_queue do |queue_id, subset_queue_id|
  puts 'after_subset_queue - run after the previous subset of tests'
end

KnapsackPro::Hooks::Queue.after_queue do |queue_id|
  puts 'after_queue - run after the test suite'
end

RSpec​

For legacy versions of knapsack_pro older than 7.0, please click here.

If you use Knapsack Pro in Queue Mode with RSpec hooks:

before(:suite) { ... }
after(:suite) { ... }

Then you need to start using Queue Mode hooks:

KnapsackPro::Hooks::Queue.before_queue { ... }
KnapsackPro::Hooks::Queue.after_queue { ... }

Otherwise, Knapsack Pro would call before(:suite) and after(:suite) for each batch of tests fetched from the Queue API.

For example, what follows are the hooks run with two batches of tests:

before_queue

# First batch of tests from Knapsack Pro API
before :suite
first_spec.rb
second_spec.rb
after :suite

# Second batch of tests from Knapsack Pro API
before :suite
third_spec.rb
fourth_spec.rb
after :suite

after_queue

Here are examples of how to define hooks properly so that they are called only once:

spec_helper.rb
before_suite_block = proc {
  puts 'RSpec before suite hook called only once'
}

unless KnapsackPro::Config::Env.queue_recording_enabled?
  RSpec.configure do |config|
    config.before(:suite) do
      before_suite_block.call
      puts 'Run this only when not using Knapsack Pro Queue Mode'
    end
  end
end

KnapsackPro::Hooks::Queue.before_queue do |queue_id|
  before_suite_block.call
  puts 'Run this only when using Knapsack Pro Queue Mode'
  puts 'This code is executed within the context of RSpec before(:suite) hook'
end

Get tests and the status of each batch of tests in RSpec​

The KnapsackPro::Hooks::Queue.before_subset_queue and KnapsackPro::Hooks::Queue.after_subset_queue hooks get a 3rd variable - the queue.

The queue variable stores an enumerable collection with each batch of tests fetched from the Queue API. The batch has:

  • a list of test file paths (KnapsackPro::Batch#test_file_paths returns an array like ['a_spec.rb', 'b_spec.rb'])
  • a status of the given set of tests in the batch (KnapsackPro::Batch#status returns :not_executed, :passed or :failed)

Example usage:

spec_helper.rb
KnapsackPro::Hooks::Queue.before_subset_queue do |queue_id, subset_queue_id, queue|
  print "Tests from all batches fetched from the Queue API so far:  "
  puts queue.map(&:test_file_paths).inspect

  queue.each(&:test_file_paths) # you can use each as well

  print "Current batch tests: "
  puts queue.current_batch.test_file_paths.inspect

  print "Current batch status: "
  puts queue.current_batch.status # returns :not_executed in the `before_subset_queue` hook
end

KnapsackPro::Hooks::Queue.after_subset_queue do |queue_id, subset_queue_id, queue|
  print "Tests from all batches fetched from the Queue API so far: "
  puts queue.map(&:test_file_paths).inspect

  print "Current batch tests: "
  puts queue.current_batch.test_file_paths.inspect

  print "Current batch status: "
  puts queue.current_batch.status # returns :passed or :failed in the `after_subset_queue` hook
end

percy-capybara​

percy-capybara >= 4​

If you are using Knapsack Pro in Queue Mode with percy-capybara >= 4, you need to configure the environment variables as explained in Percy's docs.

After that, you can use the following command:

npx percy exec --parallel -- rake knapsack_pro:queue:rspec
# or with the knapsack_pro binary
npx percy exec --parallel -- knapsack_pro queue:rspec

Here you can find the docs for the knapsack_pro binary.

percy-capybara < 4 (legacy)​

For legacy versions of knapsack_pro older than 7.0, please click here.

If you are using Knapsack Pro in Queue Mode with percy-capybara < 4 and RSpec, replace:

before(:suite) { Percy::Capybara.initialize_build }
after(:suite) { Percy::Capybara.finalize_build }

with:

KnapsackPro::Hooks::Queue.before_queue { |queue_id| Percy::Capybara.initialize_build }
KnapsackPro::Hooks::Queue.after_queue { |queue_id| Percy::Capybara.finalize_build }

Otherwise, Knapsack Pro would call before(:suite) and after(:suite) for each batch of tests fetched from the Queue API.