net: add test for RawConn.Control on Windows

This is a followup to https://go-review.googlesource.com/37039.

Updates #19435.

Change-Id: Ia795bd5158d26effa56e897698208ccf73f9e0d2
Reviewed-on: https://go-review.googlesource.com/43693
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/rawconn_unix_test.go

@@ -0,0 +1,94 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package net
+
+import (
+	"bytes"
+	"syscall"
+	"testing"
+)
+
+func TestRawConn(t *testing.T) {
+	handler := func(ls *localServer, ln Listener) {
+		c, err := ln.Accept()
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		defer c.Close()
+		var b [32]byte
+		n, err := c.Read(b[:])
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		if _, err := c.Write(b[:n]); err != nil {
+			t.Error(err)
+			return
+		}
+	}
+	ls, err := newLocalServer("tcp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ls.teardown()
+	if err := ls.buildup(handler); err != nil {
+		t.Fatal(err)
+	}
+
+	c, err := Dial(ls.Listener.Addr().Network(), ls.Listener.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	cc, err := c.(*TCPConn).SyscallConn()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var operr error
+	data := []byte("HELLO-R-U-THERE")
+	err = cc.Write(func(s uintptr) bool {
+		_, operr = syscall.Write(int(s), data)
+		if operr == syscall.EAGAIN {
+			return false
+		}
+		return true
+	})
+	if err != nil || operr != nil {
+		t.Fatal(err, operr)
+	}
+
+	var nr int
+	var b [32]byte
+	err = cc.Read(func(s uintptr) bool {
+		nr, operr = syscall.Read(int(s), b[:])
+		if operr == syscall.EAGAIN {
+			return false
+		}
+		return true
+	})
+	if err != nil || operr != nil {
+		t.Fatal(err, operr)
+	}
+	if bytes.Compare(b[:nr], data) != 0 {
+		t.Fatalf("got %#v; want %#v", b[:nr], data)
+	}
+
+	fn := func(s uintptr) {
+		operr = syscall.SetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
+	}
+	err = cc.Control(fn)
+	if err != nil || operr != nil {
+		t.Fatal(err, operr)
+	}
+	c.Close()
+	err = cc.Control(fn)
+	if err == nil {
+		t.Fatal("should fail")
+	}
+}