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