1 files changed, 33 insertions, 0 deletions
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 6cc2897f5f..6b8e6b58ce 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1776,4 +1776,37 @@ End
       end
     end
   end
+
+  def test_fcntl_lock
+    return if /x86_64-linux/ !~ RUBY_PLATFORM # A binary form of struct flock depend on platform
+
+    pad=0
+    Tempfile.open(self.class.name) do |f|
+      r, w = IO.pipe
+      pid = fork do
+        r.close
+        lock = [Fcntl::F_WRLCK, IO::SEEK_SET, pad, 12, 34, 0].pack("s!s!i!L!L!i!")
+        f.fcntl Fcntl::F_SETLKW, lock
+        w.syswrite "."
+        sleep
+      end
+      w.close
+      assert_equal ".", r.read(1)
+      r.close
+      pad = 0
+      getlock = [Fcntl::F_WRLCK, 0, pad, 0, 0, 0].pack("s!s!i!L!L!i!")
+      f.fcntl Fcntl::F_GETLK, getlock
+
+      ptype, whence, pad, start, len, lockpid = getlock.unpack("s!s!i!L!L!i!")
+
+      assert_equal(ptype, Fcntl::F_WRLCK)
+      assert_equal(whence, IO::SEEK_SET)
+      assert_equal(start, 12)
+      assert_equal(len, 34)
+      assert_equal(pid, lockpid)
+
+      Process.kill :TERM, pid
+      Process.waitpid2(pid)
+    end
+  end
 end