Make the CI Queue reporters work in parallel

ruby/lib/minitest/queue/order_reporter.rb

@@ -4,21 +4,29 @@
 class Minitest::Queue::OrderReporter < Minitest::Reporters::BaseReporter
   def initialize(options = {})
     @path = options.delete(:path)
+    @file = nil
     super
   end
 
   def start
-    @file = File.open(@path, 'w+')
     super
+    file.truncate(0)
   end
 
   def before_test(test)
     super
-    @file.puts("#{test.class.name}##{test.name}")
-    @file.flush
+    file.puts("#{test.class.name}##{test.name}")
+    file.flush
   end
 
   def report
-    @file.close
+    file.close
+  end
+
+  private
+
+  def file
+    @file ||= File.open(@path, 'a+')
   end
 end
+

ruby/test/integration/grind_redis_test.rb

@@ -97,7 +97,7 @@ def test_grind_command_runs_tests
 
     def test_grind_max_time
       grind_count = 1000000
-      timeout = RUBY_ENGINE == "truffleruby" ? 10 : 1
+      timeout = self.class.truffleruby? ? 10 : 1
 
       start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
       _, err = capture_subprocess_io do

ruby/test/integration/minitest_redis_test.rb

@@ -673,7 +673,7 @@ def test_test_data_time_reporter
                     .sort_by { |h| "#{h[:test_id]}##{h[:test_index]}" }
                     .first
 
-      start_delta = RUBY_ENGINE == "truffleruby" ? 15 : 5
+      start_delta = self.class.truffleruby? ? 15 : 5
       assert_in_delta start_time.to_i, failure[:test_start_timestamp], start_delta, "start time"
       assert_in_delta end_time.to_i, failure[:test_finish_timestamp], 5
       assert failure[:test_finish_timestamp] > failure[:test_start_timestamp]

ruby/test/minitest/queue/order_reporter_test.rb

@@ -7,16 +7,41 @@ class OrderReporterTest < Minitest::Test
 
     def setup
       @reporter = OrderReporter.new(path: log_path)
+    end
+
+    def test_start
       @reporter.start
+      @reporter.report
+      assert_equal [], File.readlines(log_path).map(&:chomp)
     end
 
     def test_before_test
+      @reporter.start
       @reporter.before_test(runnable('a'))
       @reporter.before_test(runnable('b'))
       @reporter.report
       assert_equal ['Minitest::Test#a', 'Minitest::Test#b'], File.readlines(log_path).map(&:chomp)
     end
 
+    unless truffleruby?
+      def test_forking
+        pid = fork do
+          @reporter.start
+        end
+        pids = 5.times.map do
+          fork do
+            @reporter.before_test(runnable(Process.pid))
+            @reporter.report
+          end
+        end
+        (pids + [pid]).map do |pid|
+          Process.waitpid(pid)
+        end
+
+        assert_equal pids.map { |pid| "Minitest::Test##{pid}" }.sort, File.readlines(log_path).map(&:chomp).sort
+      end
+    end
+
     private
 
     def delete_log

ruby/test/test_helper.rb

@@ -19,3 +19,12 @@
 Dir[File.expand_path('../support/**/*.rb', __FILE__)].sort.each do |file|
   require file
 end
+
+
+class Minitest::Test
+  class << self
+    def truffleruby?
+      RUBY_ENGINE == "truffleruby"
+    end
+  end
+end