Module: SimpleCov::ParallelAdapters

Defined in:
lib/simplecov/parallel_adapters.rb,
lib/simplecov/parallel_adapters/base.rb,
lib/simplecov/parallel_adapters/generic.rb,
lib/simplecov/parallel_adapters/parallel_tests.rb

Overview

Registry + selection for parallel-test-runner adapters. An adapter answers a small fixed set of questions on SimpleCov’s behalf:

- `active?` — are WE the runner in charge for this process?
- `first_worker?` — should this process do the final-result work?
- `wait_for_siblings` — block until siblings finish (optional)
- `expected_worker_count` — how many workers total

‘SimpleCov::ParallelAdapters::Base` provides safe no-op defaults; two adapters ship out of the box:

- `ParallelTestsAdapter` — wraps the grosser/parallel_tests gem
  (precise sync + first-process detection via the gem's own API).
- `GenericAdapter` — env-var-only detection for runners that follow
  the parallel_tests `TEST_ENV_NUMBER` convention but don't ship a
  Ruby API (parallel_rspec, custom CI sharding, knapsack-style
  splitters). See https://github.com/simplecov-ruby/simplecov/issues/1065.

Users can plug in additional adapters:

SimpleCov::ParallelAdapters.register MyRunnerAdapter

An adapter just needs to be a class responding to the four methods above. Subclass ‘SimpleCov::ParallelAdapters::Base` to inherit the no-op defaults and override only what you need (the contract methods are defined as class methods, so plain inheritance is what carries them through; `extend Base` won’t pick them up).

Defined Under Namespace

Classes: Base, GenericAdapter, ParallelTestsAdapter

Class Method Summary collapse

Class Method Details

.adapters ⇒ Object

Adapters in selection order. ParallelTestsAdapter first (most specific — uses the gem’s own API when the gem is loaded); then GenericAdapter as the env-var fallback. User-registered adapters are prepended (#register puts new entries at the front) so downstream code can override the built-ins by registering a more specific match.



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# File 'lib/simplecov/parallel_adapters.rb', line 44

def adapters
  @adapters ||= [ParallelTestsAdapter, GenericAdapter]
end

.current ⇒ Object

The adapter SimpleCov should consult for this process — the first registered adapter whose ‘active?` returns true. Returns nil when no adapter is active (i.e., we’re not running under any recognized parallel test runner), in which case the caller should treat the process as single-worker.



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# File 'lib/simplecov/parallel_adapters.rb', line 71

def current
  return @current if defined?(@current)

  @current = adapters.find(&:active?)
end

.register(adapter) ⇒ Object

Register a custom adapter. Newly registered adapters are inserted at the front of the selection list so a custom adapter for a specific runner takes precedence over the built-in ParallelTests and Generic adapters.

class MyRunnerAdapter < SimpleCov::ParallelAdapters::Base
  def self.active?       = ENV["MY_RUNNER_PID"]
  def self.first_worker? = ENV["MY_RUNNER_PID"].to_i == 1
  def self.expected_worker_count = ENV["MY_RUNNER_WORKERS"].to_i
end

SimpleCov::ParallelAdapters.register MyRunnerAdapter



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# File 'lib/simplecov/parallel_adapters.rb', line 60

def register(adapter)
  reset_current!
  adapters.unshift(adapter) unless adapters.include?(adapter)
  adapter
end

.reset_current! ⇒ Object

Clear the memoized ‘current` selection. Primarily for tests that mutate env vars between examples; production runs are single-shot.



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# File 'lib/simplecov/parallel_adapters.rb', line 79

def reset_current!
  remove_instance_variable(:@current) if defined?(@current)
end