Introduce duration provider pattern

.rubocop.yml

@@ -27,6 +27,8 @@ Naming/FileName:
     - lib/flatware-*.rb
 Style/Documentation:
   Enabled: false
+Metrics/AbcSize:
+  Max: 20
 Metrics/BlockLength:
   Exclude:
     - spec/**/*_spec.rb

lib/flatware/rspec.rb

@@ -11,8 +11,8 @@ module RSpec
 
     module_function
 
-    def extract_jobs_from_args(args, workers:)
-      JobBuilder.new(args, workers: workers).jobs
+    def extract_jobs_from_args(args, workers:, duration_provider:)
+      JobBuilder.new(args, workers: workers, duration_provider: duration_provider).jobs
     end
 
     def runner

lib/flatware/rspec/cli.rb

@@ -2,20 +2,28 @@
 
 require 'flatware/cli'
 require 'flatware/rspec'
+require 'flatware/rspec/duration_providers'
 require 'flatware/rspec/formatters/console'
 
 module Flatware
-  # rspec thor command
   class CLI
     worker_option
     method_option(
       'sink-endpoint',
       type: :string,
       default: 'drbunix:flatware-sink'
     )
+    method_option(
+      :'duration-provider',
+      aliases: '-d',
+      type: :string,
+      default: :example_statuses,
+      desc: 'Duration provider to use. The default option is "example_statuses".'
+    )
     desc 'rspec [FLATWARE_OPTS]', 'parallelizes rspec'
     def rspec(*rspec_args)
-      jobs = RSpec.extract_jobs_from_args rspec_args, workers: workers
+      duration_provider = RSpec::DurationProviders.lookup(options['duration-provider'])
+      jobs = RSpec.extract_jobs_from_args rspec_args, workers: workers, duration_provider: duration_provider
 
       formatter = Flatware::RSpec::Formatters::Console.new(
         ::RSpec.configuration.output_stream,

lib/flatware/rspec/duration_providers.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require 'flatware/rspec/duration_providers/example_statuses_provider'
+
+module Flatware
+  module RSpec
+    module DurationProviders
+      module_function
+
+      def lookup(provider)
+        const_get("#{classify(provider)}Provider").new
+      end
+
+      def classify(underscore_name)
+        underscore_name.to_s.split('_').map(&:capitalize).join
+      end
+
+      private_class_method :classify
+    end
+  end
+end

lib/flatware/rspec/duration_providers/example_statuses_provider.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require 'forwardable'
+
+module Flatware
+  module RSpec
+    module DurationProviders
+      class ExampleStatusesProvider
+        extend Forwardable
+        attr_reader :configuration
+
+        def_delegators :configuration, :example_status_persistence_file_path
+
+        def initialize(configuration: ::RSpec.configuration)
+          @configuration = configuration
+        end
+
+        def seconds_per_file
+          sum_seconds(load_persisted_example_statuses)
+        end
+
+        private
+
+        def load_persisted_example_statuses
+          ::RSpec::Core::ExampleStatusPersister.load_from(
+            example_status_persistence_file_path || ''
+          )
+        end
+
+        def sum_seconds(statuses)
+          statuses.select(&passing)
+                  .map { |example| parse_example(**example) }
+                  .reduce({}) do |times, example|
+            times.merge(
+              example.fetch(:file_name) => example.fetch(:seconds)
+            ) do |_, old = 0, new|
+              old + new
+            end
+          end
+        end
+
+        def passing
+          ->(example) { example.fetch(:status) =~ /pass/i }
+        end
+
+        def parse_example(example_id:, run_time:, **)
+          seconds = run_time.match(/\d+(\.\d+)?/).to_s.to_f
+          file_name = ::RSpec::Core::Example.parse_id(example_id).first
+          { seconds: seconds, file_name: file_name }
+        end
+      end
+    end
+  end
+end

lib/flatware/rspec/job_builder.rb

@@ -9,17 +9,14 @@ module RSpec
     # and attempts to ballence the jobs accordingly.
     class JobBuilder
       extend Forwardable
-      attr_reader :args, :workers, :configuration
+      attr_reader :args, :workers, :configuration, :duration_provider
 
-      def_delegators(
-        :configuration,
-        :files_to_run,
-        :example_status_persistence_file_path
-      )
+      def_delegators :configuration, :files_to_run
 
-      def initialize(args, workers:)
+      def initialize(args, workers:, duration_provider:)
         @args = args
         @workers = workers
+        @duration_provider = duration_provider
 
         @configuration = ::RSpec.configuration
         configuration.define_singleton_method(:command) { 'rspec' }
@@ -29,7 +26,7 @@ def initialize(args, workers:)
 
       def jobs
         timed_files, untimed_files = timed_and_untimed_files(
-          sum_seconds(load_persisted_example_statuses)
+          duration_provider.seconds_per_file
         )
 
         balance_jobs(
@@ -66,34 +63,6 @@ def normalize_path(path)
         ::RSpec::Core::Metadata.relative_path(File.expand_path(path))
       end
 
-      def load_persisted_example_statuses
-        ::RSpec::Core::ExampleStatusPersister.load_from(
-          example_status_persistence_file_path || ''
-        )
-      end
-
-      def sum_seconds(statuses)
-        statuses.select(&passing)
-                .map { |example| parse_example(**example) }
-                .reduce({}) do |times, example|
-          times.merge(
-            example.fetch(:file_name) => example.fetch(:seconds)
-          ) do |_, old = 0, new|
-            old + new
-          end
-        end
-      end
-
-      def passing
-        ->(example) { example.fetch(:status) =~ /pass/i }
-      end
-
-      def parse_example(example_id:, run_time:, **)
-        seconds = run_time.match(/\d+(\.\d+)?/).to_s.to_f
-        file_name = ::RSpec::Core::Example.parse_id(example_id).first
-        { seconds: seconds, file_name: file_name }
-      end
-
       def round_robin(count, items)
         Array.new(count) { [] }.tap do |groups|
           items.each_with_index do |entry, i|

spec/flatware/rspec/duration_providers/example_statuses_provider_spec.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'flatware/rspec/duration_providers/example_statuses_provider'
+
+describe Flatware::RSpec::DurationProviders::ExampleStatusesProvider do
+  before do
+    allow(RSpec::Core::ExampleStatusPersister).to(
+      receive(:load_from).and_return(persisted_examples)
+    )
+  end
+
+  let(:persisted_examples) do
+    [
+      { example_id: './fast_1_spec.rb[1]', run_time: '1 second' },
+      { example_id: './fast_2_spec.rb[1]', run_time: '1 second' },
+      { example_id: './fast_3_spec.rb[1]', run_time: '1 second' },
+      { example_id: './slow_spec.rb[1]', run_time: '2 seconds' }
+    ].map { |example| example.merge status: 'passed' }
+  end
+
+  describe '#seconds_per_file' do
+    subject { described_class.new.seconds_per_file }
+
+    it 'returns an object of the specified provider class' do
+      expect(subject).to eq(
+        './fast_1_spec.rb' => 1.0,
+        './fast_2_spec.rb' => 1.0,
+        './fast_3_spec.rb' => 1.0,
+        './slow_spec.rb' => 2.0
+      )
+    end
+  end
+end

spec/flatware/rspec/duration_providers_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'flatware/rspec/duration_providers'
+
+describe Flatware::RSpec::DurationProviders do
+  describe '#lookup' do
+    before do
+      Flatware::RSpec::DurationProviders.const_set(:MockProvider, mock_provider)
+    end
+
+    after do
+      Flatware::RSpec::DurationProviders.send(:remove_const, :MockProvider)
+    end
+
+    let(:mock_provider) { Class.new }
+
+    it 'returns an object of the specified provider class' do
+      expect(described_class.lookup('mock')).to be_a(mock_provider)
+    end
+
+    it 'works with a string argument' do
+      expect(described_class.lookup(:mock)).to be_a(mock_provider)
+    end
+  end
+end

spec/flatware/rspec/job_builder_spec.rb

@@ -5,30 +5,27 @@
 
 describe Flatware::RSpec::JobBuilder do
   before do
-    allow(RSpec::Core::ExampleStatusPersister).to(
-      receive(:load_from).and_return(persisted_examples)
-    )
-
     allow(RSpec.configuration).to(
       receive(:files_to_run).and_return(files_to_run)
     )
   end
 
-  let(:persisted_examples) { [] }
+  let(:duration_provider) { double('duration_provider', seconds_per_file: seconds_per_file) }
+  let(:seconds_per_file) { [] }
   let(:files_to_run) { [] }
 
   subject do
-    described_class.new([], workers: 2).jobs
+    described_class.new([], workers: 2, duration_provider: duration_provider).jobs
   end
 
   context 'when this run includes persisted examples' do
-    let(:persisted_examples) do
-      [
-        { example_id: './fast_1_spec.rb[1]', run_time: '1 second' },
-        { example_id: './fast_2_spec.rb[1]', run_time: '1 second' },
-        { example_id: './fast_3_spec.rb[1]', run_time: '1 second' },
-        { example_id: './slow_spec.rb[1]', run_time: '2 seconds' }
-      ].map { |example| example.merge status: 'passed' }
+    let(:seconds_per_file) do
+      {
+        './fast_1_spec.rb' => 1.0,
+        './fast_2_spec.rb' => 1.0,
+        './fast_3_spec.rb' => 1.0,
+        './slow_spec.rb' => 2.0
+      }
     end
 
     let(:files_to_run) { %w[fast_1_spec.rb fast_2_spec.rb slow_spec.rb] }