1 files changed, 69 insertions, 0 deletions
diff --git a/test/test_sync.rb b/test/test_sync.rb
new file mode 100644
index 0000000000..e3294ff824
--- /dev/null
+++ b/test/test_sync.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: false
+require 'test/unit'
+require 'sync'
+require 'timeout'
+
+class SyncTest < Test::Unit::TestCase
+  class Tester
+    include Sync_m
+  end
+
+  def test_sync_lock_and_wakeup
+    tester = Tester.new
+
+    tester.sync_lock(:EX)
+
+    t = Thread.new { tester.sync_lock(:EX) }
+
+    sleep 0.1 until t.stop?
+    t.wakeup
+    sleep 0.1 until t.stop?
+
+    assert_equal(tester.sync_waiting.uniq, tester.sync_waiting)
+  ensure
+    t.kill
+    t.join
+  end
+
+  def test_sync_upgrade_and_wakeup
+    tester = Tester.new
+    tester.sync_lock(:SH)
+
+    t = Thread.new do
+      tester.sync_lock(:SH)
+      tester.sync_lock(:EX)
+    end
+
+    sleep 0.1 until t.stop?
+    t.wakeup
+    sleep 0.1 until t.stop?
+
+    tester.sync_upgrade_waiting.each { |ary|
+      assert(!tester.sync_waiting.include?(ary[0]))
+    }
+    assert_equal(tester.sync_waiting.uniq, tester.sync_waiting)
+    assert_equal(tester.sync_waiting, [])
+  ensure
+    t.kill
+    t.join
+  end
+
+  def test_sync_lock_and_raise
+    tester= Tester.new
+    tester.sync_lock(:EX)
+
+    t = Thread.new {
+      assert_raise(RuntimeError) {
+        tester.sync_lock(:EX)
+      }
+    }
+
+    sleep 0.1 until t.stop?
+    sleep 1 if RubyVM::MJIT.enabled? # t.stop? behaves unexpectedly with --jit-wait
+    t.raise
+    t.join
+
+    assert_equal(tester.sync_waiting.uniq, tester.sync_waiting)
+    assert_equal(tester.sync_waiting, [])
+  end
+end