Add custom parallel rspec runner

A custom parallel rspec runner based on Knapsack runner
which takes in additional option for a file containing
list of test files.

When executing RSpec in CI, the list of tests allocated by Knapsack
will be compared with the test files listed in the file.

Only the test files allocated by Knapsack and listed in the file
would be executed in the CI node.

scripts/rspec_helpers.sh

@@ -56,7 +56,7 @@ function update_tests_mapping() {
 }
 
 function crystalball_rspec_data_exists() {
-  compgen -G "crystalball/rspec*.yml" > /dev/null;
+  compgen -G "crystalball/rspec*.yml" >/dev/null
 }
 
 function rspec_simple_job() {
@@ -117,7 +117,13 @@ function rspec_paralellized_job() {
 
   export MEMORY_TEST_PATH="tmp/memory_test/${report_name}_memory.csv"
 
-  knapsack rspec "-Ispec -rspec_helper --color --format documentation --format RspecJunitFormatter --out junit_rspec.xml ${rspec_opts}"
+  local rspec_args="-Ispec -rspec_helper --color --format documentation --format RspecJunitFormatter --out junit_rspec.xml ${rspec_opts}"
+
+  if [[ -n $RSPEC_MATCHING_TESTS_ENABLED ]]; then
+    tooling/bin/parallel_rspec --rspec_args "${rspec_args}" --filter tmp/matching_tests.txt
+  else
+    tooling/bin/parallel_rspec --rspec_args "${rspec_args}"
+  fi
 
   date
 }

spec/tooling/lib/tooling/parallel_rspec_runner_spec.rb

+# frozen_string_literal: true
+
+require_relative '../../../../tooling/lib/tooling/parallel_rspec_runner'
+
+RSpec.describe Tooling::ParallelRSpecRunner do # rubocop:disable RSpec/FilePath
+  describe '#run' do
+    let(:allocator) { instance_double(Knapsack::Allocator) }
+    let(:rspec_args) { '--seed 123' }
+    let(:filter_tests_file) { 'tests.txt' }
+    let(:node_tests) { %w[01_spec.rb 03_spec.rb 05_spec.rb] }
+    let(:filter_tests) { '01_spec.rb 02_spec.rb 03_spec.rb' }
+    let(:test_dir) { 'spec' }
+
+    before do
+      allow(Knapsack.logger).to receive(:info)
+      allow(allocator).to receive(:node_tests).and_return(node_tests)
+      allow(allocator).to receive(:test_dir).and_return(test_dir)
+      allow(File).to receive(:exist?).with(filter_tests_file).and_return(true)
+      allow(File).to receive(:read).and_call_original
+      allow(File).to receive(:read).with(filter_tests_file).and_return(filter_tests)
+      allow(subject).to receive(:exec)
+    end
+
+    subject { described_class.new(allocator: allocator, filter_tests_file: filter_tests_file, rspec_args: rspec_args) }
+
+    shared_examples 'runs node tests' do
+      it 'runs rspec with tests allocated for this node' do
+        expect_command(%w[bundle exec rspec --seed 123 --default-path spec -- 01_spec.rb 03_spec.rb 05_spec.rb])
+
+        subject.run
+      end
+    end
+
+    context 'given filter tests' do
+      it 'reads filter tests file for list of tests' do
+        expect(File).to receive(:read).with(filter_tests_file)
+
+        subject.run
+      end
+
+      it 'runs rspec filter tests that are allocated for this node' do
+        expect_command(%w[bundle exec rspec --seed 123 --default-path spec -- 01_spec.rb 03_spec.rb])
+
+        subject.run
+      end
+    end
+
+    context 'with empty filter tests file' do
+      let(:filter_tests) { '' }
+
+      it_behaves_like 'runs node tests'
+    end
+
+    context 'without filter_tests_file option' do
+      let(:filter_tests_file) { nil }
+
+      it_behaves_like 'runs node tests'
+    end
+
+    context 'if filter_tests_file does not exist' do
+      before do
+        allow(File).to receive(:exist?).with(filter_tests_file).and_return(false)
+      end
+
+      it_behaves_like 'runs node tests'
+    end
+
+    context 'without rspec args' do
+      let(:rspec_args) { nil }
+
+      it 'runs rspec with without extra arguments' do
+        expect_command(%w[bundle exec rspec --default-path spec -- 01_spec.rb 03_spec.rb])
+
+        subject.run
+      end
+    end
+
+    def expect_command(cmd)
+      expect(subject).to receive(:exec).with(*cmd)
+    end
+  end
+end

tooling/bin/parallel_rspec

+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'optparse'
+require_relative '../lib/tooling/parallel_rspec_runner'
+
+options = {}
+
+OptionParser.new do |opts|
+  opts.on("--rspec_args rspec_args", String, "Optional rspec arguments") do |value|
+    options[:rspec_args] = value
+  end
+
+  opts.on("--filter filter_tests_file", String, "Optional filename containing tests to be filtered") do |value|
+    options[:filter_tests_file] = value
+  end
+end.parse!
+
+Tooling::ParallelRSpecRunner.run(options)

tooling/lib/tooling/parallel_rspec_runner.rb

+# frozen_string_literal: true
+
+require 'knapsack'
+
+# A custom parallel rspec runner based on Knapsack runner
+# which takes in additional option for a file containing
+# list of test files.
+#
+# When executing RSpec in CI, the list of tests allocated by Knapsack
+# will be compared with the test files listed in the file.
+#
+# Only the test files allocated by Knapsack and listed in the file
+# would be executed in the CI node.
+module Tooling
+  class ParallelRSpecRunner
+    def self.run(rspec_args: nil, filter_tests_file: nil)
+      new(rspec_args: rspec_args, filter_tests_file: filter_tests_file).run
+    end
+
+    def initialize(allocator: knapsack_allocator, filter_tests_file: nil, rspec_args: nil)
+      @allocator = allocator
+      @filter_tests_file = filter_tests_file
+      @rspec_args = rspec_args&.split(' ') || []
+    end
+
+    def run
+      Knapsack.logger.info
+      Knapsack.logger.info 'Knapsack node specs:'
+      Knapsack.logger.info node_tests
+      Knapsack.logger.info
+      Knapsack.logger.info 'Filter specs:'
+      Knapsack.logger.info filter_tests
+      Knapsack.logger.info
+      Knapsack.logger.info 'Running specs:'
+      Knapsack.logger.info tests_to_run
+      Knapsack.logger.info
+
+      exec(*rspec_command)
+    end
+
+    private
+
+    attr_reader :allocator, :filter_tests_file, :rspec_args
+
+    def rspec_command
+      %w[bundle exec rspec].tap do |cmd|
+        cmd.push(*rspec_args)
+        cmd.push('--default-path', allocator.test_dir)
+        cmd.push('--')
+        cmd.push(*tests_to_run)
+      end
+    end
+
+    def tests_to_run
+      return node_tests if filter_tests.empty?
+
+      node_tests & filter_tests
+    end
+
+    def node_tests
+      allocator.node_tests
+    end
+
+    def filter_tests
+      filter_tests_file ? tests_from_file(filter_tests_file) : []
+    end
+
+    def tests_from_file(filter_tests_file)
+      return [] unless File.exist?(filter_tests_file)
+
+      File.read(filter_tests_file).split(' ')
+    end
+
+    def knapsack_allocator
+      Knapsack::AllocatorBuilder.new(Knapsack::Adapters::RSpecAdapter).allocator
+    end
+  end
+end