Run tests in parallel via parallel_tests

Uses the parallel_tests gem to execute tests in multiple processes
simultaneously on the same machine.

Adds the `--parallel` CLI option that instructs the QA framework
to use the parallel_tests executable.

Tests need access to global state contained in `Runtime::Scenario`
so when `--parallel` is invoked `Runtime::Scenario` is serialized
to an environment variable, which is passed to parallel_tests,
and then deserialized in `spec_helper`.

6 files changed, 88 insertions, 24 deletions

diff --git a/qa/qa/runtime/browser.rb b/qa/qa/runtime/browser.rb
index ed0779b93cc..2987bb1a213 100644
--- a/qa/qa/runtime/browser.rb
+++ b/qa/qa/runtime/browser.rb
@@ -13,6 +13,8 @@ module QA
 
       NotRespondingError = Class.new(RuntimeError)
 
+      CAPYBARA_MAX_WAIT_TIME = 10
+
       def initialize
         self.class.configure!
       end
@@ -43,6 +45,8 @@ module QA
           end
         end
 
+        Capybara.server_port = 9887 + ENV['TEST_ENV_NUMBER'].to_i
+
         return if Capybara.drivers.include?(:chrome)
 
         Capybara.register_driver QA::Runtime::Env.browser do |app|
@@ -119,7 +123,7 @@ module QA
         Capybara.configure do |config|
           config.default_driver = QA::Runtime::Env.browser
           config.javascript_driver = QA::Runtime::Env.browser
-          config.default_max_wait_time = 10
+          config.default_max_wait_time = CAPYBARA_MAX_WAIT_TIME
           # https://github.com/mattheworiordan/capybara-screenshot/issues/164
           config.save_path = ::File.expand_path('../../tmp', __dir__)
         end
diff --git a/qa/qa/runtime/env.rb b/qa/qa/runtime/env.rb
index 96f337dc081..d50f618ff82 100644
--- a/qa/qa/runtime/env.rb
+++ b/qa/qa/runtime/env.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'gitlab/qa'
+
 module QA
   module Runtime
     module Env
@@ -7,6 +9,8 @@ module QA
 
       attr_writer :personal_access_token, :ldap_username, :ldap_password
 
+      ENV_VARIABLES = Gitlab::QA::Runtime::Env::ENV_VARIABLES
+
       # The environment variables used to indicate if the environment under test
       # supports the given feature
       SUPPORTED_FEATURES = {
@@ -201,6 +205,10 @@ module QA
         enabled?(ENV[SUPPORTED_FEATURES[feature]], default: true)
       end
 
+      def runtime_scenario_attributes
+        ENV['QA_RUNTIME_SCENARIO_ATTRIBUTES']
+      end
+
       private
 
       def remote_grid_credentials
diff --git a/qa/qa/runtime/scenario.rb b/qa/qa/runtime/scenario.rb
index 5067322804b..3662ebe671b 100644
--- a/qa/qa/runtime/scenario.rb
+++ b/qa/qa/runtime/scenario.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'json'
+
 module QA
   module Runtime
     ##
@@ -24,6 +26,10 @@ module QA
         end
       end
 
+      def from_env(var)
+        JSON.parse(Runtime::Env.runtime_scenario_attributes).each { |k, v| define(k, v) }
+      end
+
       def method_missing(name, *)
         raise ArgumentError, "Scenario attribute `#{name}` not defined!"
       end
diff --git a/qa/qa/scenario/shared_attributes.rb b/qa/qa/scenario/shared_attributes.rb
index 40d5c6b1ff1..52f50ec8c27 100644
--- a/qa/qa/scenario/shared_attributes.rb
+++ b/qa/qa/scenario/shared_attributes.rb
@@ -7,6 +7,7 @@ module QA
 
       attribute :gitlab_address, '--address URL', 'Address of the instance to test'
       attribute :enable_feature, '--enable-feature FEATURE_FLAG', 'Enable a feature before running tests'
+      attribute :parallel, '--parallel', 'Execute tests in parallel'
     end
   end
 end
diff --git a/qa/qa/specs/parallel_runner.rb b/qa/qa/specs/parallel_runner.rb
new file mode 100644
index 00000000000..b92fdb610b6
--- /dev/null
+++ b/qa/qa/specs/parallel_runner.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require 'open3'
+
+module QA
+  module Specs
+    module ParallelRunner
+      module_function
+
+      def run(args)
+        unless args.include?('--')
+          index = args.index { |opt| opt.include?('features') }
+
+          args.insert(index, '--') if index
+        end
+
+        env = {}
+        Runtime::Env::ENV_VARIABLES.each_key do |key|
+          env[key] = ENV[key] if ENV[key]
+        end
+        env['QA_RUNTIME_SCENARIO_ATTRIBUTES'] = Runtime::Scenario.attributes.to_json
+        env['GITLAB_QA_ACCESS_TOKEN'] = Runtime::API::Client.new(:gitlab).personal_access_token unless env['GITLAB_QA_ACCESS_TOKEN']
+
+        cmd = "bundle exec parallel_test -t rspec --combine-stderr --serialize-stdout -- #{args.flatten.join(' ')}"
+        ::Open3.popen2e(env, cmd) do |_, out, wait|
+          out.each { |line| puts line }
+
+          exit wait.value.exitstatus
+        end
+      end
+    end
+  end
+end
diff --git a/qa/qa/specs/runner.rb b/qa/qa/specs/runner.rb
index f1cb9378de8..6aa08cf77b4 100644
--- a/qa/qa/specs/runner.rb
+++ b/qa/qa/specs/runner.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
+require 'knapsack'
 require 'rspec/core'
 require 'rspec/expectations'
-require 'knapsack'
 
 module QA
   module Specs
@@ -17,44 +17,56 @@ module QA
         @options = []
       end
 
-      def perform
-        args = []
-        args.push('--tty') if tty
+      def paths_from_knapsack
+        allocator = Knapsack::AllocatorBuilder.new(Knapsack::Adapters::RSpecAdapter).allocator
+
+        QA::Runtime::Logger.info ''
+        QA::Runtime::Logger.info 'Report specs:'
+        QA::Runtime::Logger.info allocator.report_node_tests.join(', ')
+        QA::Runtime::Logger.info ''
+        QA::Runtime::Logger.info 'Leftover specs:'
+        QA::Runtime::Logger.info allocator.leftover_node_tests.join(', ')
+        QA::Runtime::Logger.info ''
+
+        ['--', allocator.node_tests]
+      end
+
+      def rspec_tags
+        tags_for_rspec = []
 
         if tags.any?
-          tags.each { |tag| args.push(['--tag', tag.to_s]) }
+          tags.each { |tag| tags_for_rspec.push(['--tag', tag.to_s]) }
         else
-          args.push(%w[--tag ~orchestrated]) unless (%w[-t --tag] & options).any?
+          tags_for_rspec.push(%w[--tag ~orchestrated]) unless (%w[-t --tag] & options).any?
         end
 
-        args.push(%w[--tag ~skip_signup_disabled]) if QA::Runtime::Env.signup_disabled?
+        tags_for_rspec.push(%w[--tag ~skip_signup_disabled]) if QA::Runtime::Env.signup_disabled?
 
         QA::Runtime::Env.supported_features.each_key do |key|
-          args.push(["--tag", "~requires_#{key}"]) unless QA::Runtime::Env.can_test? key
+          tags_for_rspec.push(%W[--tag ~requires_#{key}]) unless QA::Runtime::Env.can_test? key
         end
 
-        args.push(options)
+        tags_for_rspec
+      end
 
-        Runtime::Browser.configure!
+      def perform
+        args = []
+        args.push('--tty') if tty
+        args.push(rspec_tags)
+        args.push(options)
 
         if Runtime::Env.knapsack?
-          allocator = Knapsack::AllocatorBuilder.new(Knapsack::Adapters::RSpecAdapter).allocator
-
-          QA::Runtime::Logger.info ''
-          QA::Runtime::Logger.info 'Report specs:'
-          QA::Runtime::Logger.info allocator.report_node_tests.join(', ')
-          QA::Runtime::Logger.info ''
-          QA::Runtime::Logger.info 'Leftover specs:'
-          QA::Runtime::Logger.info allocator.leftover_node_tests.join(', ')
-          QA::Runtime::Logger.info ''
-
-          args.push(['--', allocator.node_tests])
+          args.push(paths_from_knapsack)
         else
           args.push(DEFAULT_TEST_PATH_ARGS) unless options.any? { |opt| opt =~ %r{/features/} }
         end
 
-        RSpec::Core::Runner.run(args.flatten, $stderr, $stdout).tap do |status|
-          abort if status.nonzero?
+        if Runtime::Scenario.attributes[:parallel]
+          ParallelRunner.run(args.flatten)
+        else
+          RSpec::Core::Runner.run(args.flatten, $stderr, $stdout).tap do |status|
+            abort if status.nonzero?
+          end
         end
       end
     end