Support `IO#pread` / `IO#pwrite` using fiber scheduler. (#7594)

* Skip test if non-blocking file IO is not supported.

1 files changed, 41 insertions, 0 deletions

diff --git a/test/fiber/test_io_buffer.rb b/test/fiber/test_io_buffer.rb
index 3de70200d5..a08b1ce1a9 100644
--- a/test/fiber/test_io_buffer.rb
+++ b/test/fiber/test_io_buffer.rb
@@ -155,4 +155,45 @@ class TestFiberIOBuffer < Test::Unit::TestCase
     i&.close
     o&.close
   end
+
+  def nonblockable?(io)
+    io.nonblock{}
+    true
+  rescue
+    false
+  end
+
+  def test_io_buffer_pread_pwrite
+    file = Tempfile.new("test_io_buffer_pread_pwrite")
+
+    omit "Non-blocking file IO is not supported" unless nonblockable?(file)
+
+    source_buffer = IO::Buffer.for("Hello World!")
+    destination_buffer = IO::Buffer.new(source_buffer.size)
+
+    # Test non-scheduler code path:
+    source_buffer.pwrite(file, 1, source_buffer.size)
+    destination_buffer.pread(file, 1, source_buffer.size)
+    assert_equal source_buffer, destination_buffer
+
+    # Test scheduler code path:
+    destination_buffer.clear
+    file.truncate(0)
+
+    thread = Thread.new do
+      scheduler = IOBufferScheduler.new
+      Fiber.set_scheduler scheduler
+
+      Fiber.schedule do
+        source_buffer.pwrite(file, 1, source_buffer.size)
+        destination_buffer.pread(file, 1, source_buffer.size)
+      end
+    end
+
+    thread.join
+
+    assert_equal source_buffer, destination_buffer
+  ensure
+    file&.close!
+  end
 end