src/net/error_test.go - go - Git at Google

 // Copyright 2015 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.

 package net

 import (
 	"fmt"
 	"io"
 	"net/internal/socktest"
 	"os"
 	"runtime"
 	"testing"
 	"time"
 )

 func isTimeoutError(err error) bool {
 	nerr, ok := err.(Error)
 	return ok && nerr.Timeout()
 }

 func isTemporaryError(err error) bool {
 	nerr, ok := err.(Error)
 	return ok && nerr.Temporary()
 }

 func (e *OpError) isValid() error {
 	if e.Op == "" {
 		return fmt.Errorf("OpError.Op is empty: %v", e)
 	}
 	if e.Net == "" {
 		return fmt.Errorf("OpError.Net is empty: %v", e)
 	}
 	switch addr := e.Addr.(type) {
 	case *TCPAddr:
 		if addr == nil {
 			return fmt.Errorf("OpError.Addr is empty: %v", e)
 		}
 	case *UDPAddr:
 		if addr == nil {
 			return fmt.Errorf("OpError.Addr is empty: %v", e)
 		}
 	case *IPAddr:
 		if addr == nil {
 			return fmt.Errorf("OpError.Addr is empty: %v", e)
 		}
 	case *IPNet:
 		if addr == nil {
 			return fmt.Errorf("OpError.Addr is empty: %v", e)
 		}
 	case *UnixAddr:
 		if addr == nil {
 			return fmt.Errorf("OpError.Addr is empty: %v", e)
 		}
 	case *pipeAddr:
 		if addr == nil {
 			return fmt.Errorf("OpError.Addr is empty: %v", e)
 		}
 	}
 	if e.Err == nil {
 		return fmt.Errorf("OpError.Err is empty: %v", e)
 	}
 	return nil
 }

 // parseDialError parses nestedErr and reports whether it is a valid
 // error value from Dial, Listen functions.
 // It returns nil when nestedErr is valid.
 func parseDialError(nestedErr error) error {
 	if nestedErr == nil {
 		return nil
 	}

 	switch err := nestedErr.(type) {
 	case *OpError:
 		if err := err.isValid(); err != nil {
 			return err
 		}
 		nestedErr = err.Err
 		goto second
 	}
 	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

 second:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	switch err := nestedErr.(type) {
 	case *AddrError, addrinfoErrno, *DNSError, InvalidAddrError, *ParseError, *timeoutError, UnknownNetworkError:
 		return nil
 	case *DNSConfigError:
 		nestedErr = err.Err
 		goto third
 	case *os.SyscallError:
 		nestedErr = err.Err
 		goto third
 	}
 	switch nestedErr {
 	case errClosing, errMissingAddress:
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

 third:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
 }

 var dialErrorTests = []struct {
 	network, address string
 }{
 	{"foo", ""},
 	{"bar", "baz"},
 	{"datakit", "mh/astro/r70"},
 	{"tcp", ""},
 	{"tcp", "127.0.0.1:☺"},
 	{"tcp", "no-such-name:80"},
 	{"tcp", "mh/astro/r70:http"},

 	{"tcp", "127.0.0.1:0"},
 	{"udp", "127.0.0.1:0"},
 	{"ip:icmp", "127.0.0.1"},

 	{"unix", "/path/to/somewhere"},
 	{"unixgram", "/path/to/somewhere"},
 	{"unixpacket", "/path/to/somewhere"},
 }

 func TestDialError(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
 		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
 	}

 	origTestHookLookupIP := testHookLookupIP
 	defer func() { testHookLookupIP = origTestHookLookupIP }()
 	testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) {
 		return nil, &DNSError{Err: "dial error test", Name: "name", Server: "server", IsTimeout: true}
 	}
 	sw.Set(socktest.FilterConnect, func(so *socktest.Status) (socktest.AfterFilter, error) {
 		return nil, errOpNotSupported
 	})
 	defer sw.Set(socktest.FilterConnect, nil)

 	d := Dialer{Timeout: someTimeout}
 	for i, tt := range dialErrorTests {
 		c, err := d.Dial(tt.network, tt.address)
 		if err == nil {
 			t.Errorf("#%d: should fail; %s:%s->%s", i, tt.network, c.LocalAddr(), c.RemoteAddr())
 			c.Close()
 			continue
 		}
 		if c != nil {
 			t.Errorf("Dial returned non-nil interface %T(%v) with err != nil", c, c)
 		}
 		if err = parseDialError(err); err != nil {
 			t.Errorf("#%d: %v", i, err)
 			continue
 		}
 	}
 }

 var listenErrorTests = []struct {
 	network, address string
 }{
 	{"foo", ""},
 	{"bar", "baz"},
 	{"datakit", "mh/astro/r70"},
 	{"tcp", "127.0.0.1:☺"},
 	{"tcp", "no-such-name:80"},
 	{"tcp", "mh/astro/r70:http"},

 	{"tcp", "127.0.0.1:0"},

 	{"unix", "/path/to/somewhere"},
 	{"unixpacket", "/path/to/somewhere"},
 }

 func TestListenError(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
 		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
 	}

 	origTestHookLookupIP := testHookLookupIP
 	defer func() { testHookLookupIP = origTestHookLookupIP }()
 	testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) {
 		return nil, &DNSError{Err: "listen error test", Name: "name", Server: "server", IsTimeout: true}
 	}
 	sw.Set(socktest.FilterListen, func(so *socktest.Status) (socktest.AfterFilter, error) {
 		return nil, errOpNotSupported
 	})
 	defer sw.Set(socktest.FilterListen, nil)

 	for i, tt := range listenErrorTests {
 		ln, err := Listen(tt.network, tt.address)
 		if err == nil {
 			t.Errorf("#%d: should fail; %s:%s->", i, tt.network, ln.Addr())
 			ln.Close()
 			continue
 		}
 		if ln != nil {
 			t.Errorf("Listen returned non-nil interface %T(%v) with err != nil", ln, ln)
 		}
 		if err = parseDialError(err); err != nil {
 			t.Errorf("#%d: %v", i, err)
 			continue
 		}
 	}
 }

 var listenPacketErrorTests = []struct {
 	network, address string
 }{
 	{"foo", ""},
 	{"bar", "baz"},
 	{"datakit", "mh/astro/r70"},
 	{"udp", "127.0.0.1:☺"},
 	{"udp", "no-such-name:80"},
 	{"udp", "mh/astro/r70:http"},
 }

 func TestListenPacketError(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
 		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
 	}

 	origTestHookLookupIP := testHookLookupIP
 	defer func() { testHookLookupIP = origTestHookLookupIP }()
 	testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) {
 		return nil, &DNSError{Err: "listen error test", Name: "name", Server: "server", IsTimeout: true}
 	}

 	for i, tt := range listenPacketErrorTests {
 		c, err := ListenPacket(tt.network, tt.address)
 		if err == nil {
 			t.Errorf("#%d: should fail; %s:%s->", i, tt.network, c.LocalAddr())
 			c.Close()
 			continue
 		}
 		if c != nil {
 			t.Errorf("ListenPacket returned non-nil interface %T(%v) with err != nil", c, c)
 		}
 		if err = parseDialError(err); err != nil {
 			t.Errorf("#%d: %v", i, err)
 			continue
 		}
 	}
 }

 // parseReadError parses nestedErr and reports whether it is a valid
 // error value from Read functions.
 // It returns nil when nestedErr is valid.
 func parseReadError(nestedErr error) error {
 	if nestedErr == nil {
 		return nil
 	}

 	switch err := nestedErr.(type) {
 	case *OpError:
 		if err := err.isValid(); err != nil {
 			return err
 		}
 		nestedErr = err.Err
 		goto second
 	}
 	if nestedErr == io.EOF {
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

 second:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	switch err := nestedErr.(type) {
 	case *os.SyscallError:
 		nestedErr = err.Err
 		goto third
 	}
 	switch nestedErr {
 	case errClosing, errTimeout:
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

 third:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
 }

 // parseWriteError parses nestedErr and reports whether it is a valid
 // error value from Write functions.
 // It returns nil when nestedErr is valid.
 func parseWriteError(nestedErr error) error {
 	if nestedErr == nil {
 		return nil
 	}

 	switch err := nestedErr.(type) {
 	case *OpError:
 		if err := err.isValid(); err != nil {
 			return err
 		}
 		nestedErr = err.Err
 		goto second
 	}
 	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

 second:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	switch err := nestedErr.(type) {
 	case *os.SyscallError:
 		nestedErr = err.Err
 		goto third
 	}
 	switch nestedErr {
 	case errClosing, errTimeout, ErrWriteToConnected, io.ErrUnexpectedEOF:
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

 third:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
 }

 // parseCloseError parses nestedErr and reports whether it is a valid
 // error value from Close functions.
 // It returns nil when nestedErr is valid.
 func parseCloseError(nestedErr error) error {
 	if nestedErr == nil {
 		return nil
 	}

 	switch err := nestedErr.(type) {
 	case *OpError:
 		if err := err.isValid(); err != nil {
 			return err
 		}
 		nestedErr = err.Err
 		goto second
 	}
 	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

 second:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	switch err := nestedErr.(type) {
 	case *os.SyscallError:
 		nestedErr = err.Err
 		goto third
 	case *os.PathError: // for Plan 9
 		nestedErr = err.Err
 		goto third
 	}
 	switch nestedErr {
 	case errClosing:
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

 third:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
 }

 func TestCloseError(t *testing.T) {
 	ln, err := newLocalListener("tcp")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer ln.Close()
 	c, err := Dial(ln.Addr().Network(), ln.Addr().String())
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer c.Close()

 	for i := 0; i < 3; i++ {
 		err = c.(*TCPConn).CloseRead()
 		if perr := parseCloseError(err); perr != nil {
 			t.Errorf("#%d: %v", i, perr)
 		}
 	}
 	for i := 0; i < 3; i++ {
 		err = c.(*TCPConn).CloseWrite()
 		if perr := parseCloseError(err); perr != nil {
 			t.Errorf("#%d: %v", i, perr)
 		}
 	}
 	for i := 0; i < 3; i++ {
 		err = c.Close()
 		if perr := parseCloseError(err); perr != nil {
 			t.Errorf("#%d: %v", i, perr)
 		}
 		err = ln.Close()
 		if perr := parseCloseError(err); perr != nil {
 			t.Errorf("#%d: %v", i, perr)
 		}
 	}

 	pc, err := ListenPacket("udp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer pc.Close()

 	for i := 0; i < 3; i++ {
 		err = pc.Close()
 		if perr := parseCloseError(err); perr != nil {
 			t.Errorf("#%d: %v", i, perr)
 		}
 	}
 }

 // parseAcceptError parses nestedErr and reports whether it is a valid
 // error value from Accept functions.
 // It returns nil when nestedErr is valid.
 func parseAcceptError(nestedErr error) error {
 	if nestedErr == nil {
 		return nil
 	}

 	switch err := nestedErr.(type) {
 	case *OpError:
 		if err := err.isValid(); err != nil {
 			return err
 		}
 		nestedErr = err.Err
 		goto second
 	}
 	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

 second:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	switch err := nestedErr.(type) {
 	case *os.SyscallError:
 		nestedErr = err.Err
 		goto third
 	}
 	switch nestedErr {
 	case errClosing, errTimeout:
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

 third:
 	if isPlatformError(nestedErr) {
 		return nil
 	}
 	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
 }

 func TestAcceptError(t *testing.T) {
 	handler := func(ls *localServer, ln Listener) {
 		for {
 			ln.(*TCPListener).SetDeadline(time.Now().Add(5 * time.Millisecond))
 			c, err := ln.Accept()
 			if perr := parseAcceptError(err); perr != nil {
 				t.Error(perr)
 			}
 			if err != nil {
 				if c != nil {
 					t.Errorf("Accept returned non-nil interface %T(%v) with err != nil", c, c)
 				}
 				if !isTimeoutError(err) && !isTemporaryError(err) {
 					return
 				}
 				continue
 			}
 			c.Close()
 		}
 	}
 	ls, err := newLocalServer("tcp")
 	if err != nil {
 		t.Fatal(err)
 	}
 	if err := ls.buildup(handler); err != nil {
 		ls.teardown()
 		t.Fatal(err)
 	}

 	time.Sleep(100 * time.Millisecond)
 	ls.teardown()
 }
	// Copyright 2015 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.

	package net

	import (
	"fmt"
	"io"
	"net/internal/socktest"
	"os"
	"runtime"
	"testing"
	"time"
	)

	func isTimeoutError(err error) bool {
	nerr, ok := err.(Error)
	return ok && nerr.Timeout()
	}

	func isTemporaryError(err error) bool {
	nerr, ok := err.(Error)
	return ok && nerr.Temporary()
	}

	func (e *OpError) isValid() error {
	if e.Op == "" {
	return fmt.Errorf("OpError.Op is empty: %v", e)
	}
	if e.Net == "" {
	return fmt.Errorf("OpError.Net is empty: %v", e)
	}
	switch addr := e.Addr.(type) {
	case *TCPAddr:
	if addr == nil {
	return fmt.Errorf("OpError.Addr is empty: %v", e)
	}
	case *UDPAddr:
	if addr == nil {
	return fmt.Errorf("OpError.Addr is empty: %v", e)
	}
	case *IPAddr:
	if addr == nil {
	return fmt.Errorf("OpError.Addr is empty: %v", e)
	}
	case *IPNet:
	if addr == nil {
	return fmt.Errorf("OpError.Addr is empty: %v", e)
	}
	case *UnixAddr:
	if addr == nil {
	return fmt.Errorf("OpError.Addr is empty: %v", e)
	}
	case *pipeAddr:
	if addr == nil {
	return fmt.Errorf("OpError.Addr is empty: %v", e)
	}
	}
	if e.Err == nil {
	return fmt.Errorf("OpError.Err is empty: %v", e)
	}
	return nil
	}

	// parseDialError parses nestedErr and reports whether it is a valid
	// error value from Dial, Listen functions.
	// It returns nil when nestedErr is valid.
	func parseDialError(nestedErr error) error {
	if nestedErr == nil {
	return nil
	}

	switch err := nestedErr.(type) {
	case *OpError:
	if err := err.isValid(); err != nil {
	return err
	}
	nestedErr = err.Err
	goto second
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

	second:
	if isPlatformError(nestedErr) {
	return nil
	}
	switch err := nestedErr.(type) {
	case AddrError, addrinfoErrno, DNSError, InvalidAddrError, ParseError, timeoutError, UnknownNetworkError:
	return nil
	case *DNSConfigError:
	nestedErr = err.Err
	goto third
	case *os.SyscallError:
	nestedErr = err.Err
	goto third
	}
	switch nestedErr {
	case errClosing, errMissingAddress:
	return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

	third:
	if isPlatformError(nestedErr) {
	return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
	}

	var dialErrorTests = []struct {
	network, address string
	}{
	{"foo", ""},
	{"bar", "baz"},
	{"datakit", "mh/astro/r70"},
	{"tcp", ""},
	{"tcp", "127.0.0.1:☺"},
	{"tcp", "no-such-name:80"},
	{"tcp", "mh/astro/r70:http"},

	{"tcp", "127.0.0.1:0"},
	{"udp", "127.0.0.1:0"},
	{"ip:icmp", "127.0.0.1"},

	{"unix", "/path/to/somewhere"},
	{"unixgram", "/path/to/somewhere"},
	{"unixpacket", "/path/to/somewhere"},
	}

	func TestDialError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
	t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

	origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) {
	return nil, &DNSError{Err: "dial error test", Name: "name", Server: "server", IsTimeout: true}
	}
	sw.Set(socktest.FilterConnect, func(so *socktest.Status) (socktest.AfterFilter, error) {
	return nil, errOpNotSupported
	})
	defer sw.Set(socktest.FilterConnect, nil)

	d := Dialer{Timeout: someTimeout}
	for i, tt := range dialErrorTests {
	c, err := d.Dial(tt.network, tt.address)
	if err == nil {
	t.Errorf("#%d: should fail; %s:%s->%s", i, tt.network, c.LocalAddr(), c.RemoteAddr())
	c.Close()
	continue
	}
	if c != nil {
	t.Errorf("Dial returned non-nil interface %T(%v) with err != nil", c, c)
	}
	if err = parseDialError(err); err != nil {
	t.Errorf("#%d: %v", i, err)
	continue
	}
	}
	}

	var listenErrorTests = []struct {
	network, address string
	}{
	{"foo", ""},
	{"bar", "baz"},
	{"datakit", "mh/astro/r70"},
	{"tcp", "127.0.0.1:☺"},
	{"tcp", "no-such-name:80"},
	{"tcp", "mh/astro/r70:http"},

	{"tcp", "127.0.0.1:0"},

	{"unix", "/path/to/somewhere"},
	{"unixpacket", "/path/to/somewhere"},
	}

	func TestListenError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
	t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

	origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) {
	return nil, &DNSError{Err: "listen error test", Name: "name", Server: "server", IsTimeout: true}
	}
	sw.Set(socktest.FilterListen, func(so *socktest.Status) (socktest.AfterFilter, error) {
	return nil, errOpNotSupported
	})
	defer sw.Set(socktest.FilterListen, nil)

	for i, tt := range listenErrorTests {
	ln, err := Listen(tt.network, tt.address)
	if err == nil {
	t.Errorf("#%d: should fail; %s:%s->", i, tt.network, ln.Addr())
	ln.Close()
	continue
	}
	if ln != nil {
	t.Errorf("Listen returned non-nil interface %T(%v) with err != nil", ln, ln)
	}
	if err = parseDialError(err); err != nil {
	t.Errorf("#%d: %v", i, err)
	continue
	}
	}
	}

	var listenPacketErrorTests = []struct {
	network, address string
	}{
	{"foo", ""},
	{"bar", "baz"},
	{"datakit", "mh/astro/r70"},
	{"udp", "127.0.0.1:☺"},
	{"udp", "no-such-name:80"},
	{"udp", "mh/astro/r70:http"},
	}

	func TestListenPacketError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
	t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

	origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) {
	return nil, &DNSError{Err: "listen error test", Name: "name", Server: "server", IsTimeout: true}
	}

	for i, tt := range listenPacketErrorTests {
	c, err := ListenPacket(tt.network, tt.address)
	if err == nil {
	t.Errorf("#%d: should fail; %s:%s->", i, tt.network, c.LocalAddr())
	c.Close()
	continue
	}
	if c != nil {
	t.Errorf("ListenPacket returned non-nil interface %T(%v) with err != nil", c, c)
	}
	if err = parseDialError(err); err != nil {
	t.Errorf("#%d: %v", i, err)
	continue
	}
	}
	}

	// parseReadError parses nestedErr and reports whether it is a valid
	// error value from Read functions.
	// It returns nil when nestedErr is valid.
	func parseReadError(nestedErr error) error {
	if nestedErr == nil {
	return nil
	}

	switch err := nestedErr.(type) {
	case *OpError:
	if err := err.isValid(); err != nil {
	return err
	}
	nestedErr = err.Err
	goto second
	}
	if nestedErr == io.EOF {
	return nil
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

	second:
	if isPlatformError(nestedErr) {
	return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
	nestedErr = err.Err
	goto third
	}
	switch nestedErr {
	case errClosing, errTimeout:
	return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

	third:
	if isPlatformError(nestedErr) {
	return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
	}

	// parseWriteError parses nestedErr and reports whether it is a valid
	// error value from Write functions.
	// It returns nil when nestedErr is valid.
	func parseWriteError(nestedErr error) error {
	if nestedErr == nil {
	return nil
	}

	switch err := nestedErr.(type) {
	case *OpError:
	if err := err.isValid(); err != nil {
	return err
	}
	nestedErr = err.Err
	goto second
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

	second:
	if isPlatformError(nestedErr) {
	return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
	nestedErr = err.Err
	goto third
	}
	switch nestedErr {
	case errClosing, errTimeout, ErrWriteToConnected, io.ErrUnexpectedEOF:
	return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

	third:
	if isPlatformError(nestedErr) {
	return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
	}

	// parseCloseError parses nestedErr and reports whether it is a valid
	// error value from Close functions.
	// It returns nil when nestedErr is valid.
	func parseCloseError(nestedErr error) error {
	if nestedErr == nil {
	return nil
	}

	switch err := nestedErr.(type) {
	case *OpError:
	if err := err.isValid(); err != nil {
	return err
	}
	nestedErr = err.Err
	goto second
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

	second:
	if isPlatformError(nestedErr) {
	return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
	nestedErr = err.Err
	goto third
	case *os.PathError: // for Plan 9
	nestedErr = err.Err
	goto third
	}
	switch nestedErr {
	case errClosing:
	return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

	third:
	if isPlatformError(nestedErr) {
	return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
	}

	func TestCloseError(t *testing.T) {
	ln, err := newLocalListener("tcp")
	if err != nil {
	t.Fatal(err)
	}
	defer ln.Close()
	c, err := Dial(ln.Addr().Network(), ln.Addr().String())
	if err != nil {
	t.Fatal(err)
	}
	defer c.Close()

	for i := 0; i < 3; i++ {
	err = c.(*TCPConn).CloseRead()
	if perr := parseCloseError(err); perr != nil {
	t.Errorf("#%d: %v", i, perr)
	}
	}
	for i := 0; i < 3; i++ {
	err = c.(*TCPConn).CloseWrite()
	if perr := parseCloseError(err); perr != nil {
	t.Errorf("#%d: %v", i, perr)
	}
	}
	for i := 0; i < 3; i++ {
	err = c.Close()
	if perr := parseCloseError(err); perr != nil {
	t.Errorf("#%d: %v", i, perr)
	}
	err = ln.Close()
	if perr := parseCloseError(err); perr != nil {
	t.Errorf("#%d: %v", i, perr)
	}
	}

	pc, err := ListenPacket("udp", "127.0.0.1:0")
	if err != nil {
	t.Fatal(err)
	}
	defer pc.Close()

	for i := 0; i < 3; i++ {
	err = pc.Close()
	if perr := parseCloseError(err); perr != nil {
	t.Errorf("#%d: %v", i, perr)
	}
	}
	}

	// parseAcceptError parses nestedErr and reports whether it is a valid
	// error value from Accept functions.
	// It returns nil when nestedErr is valid.
	func parseAcceptError(nestedErr error) error {
	if nestedErr == nil {
	return nil
	}

	switch err := nestedErr.(type) {
	case *OpError:
	if err := err.isValid(); err != nil {
	return err
	}
	nestedErr = err.Err
	goto second
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

	second:
	if isPlatformError(nestedErr) {
	return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
	nestedErr = err.Err
	goto third
	}
	switch nestedErr {
	case errClosing, errTimeout:
	return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

	third:
	if isPlatformError(nestedErr) {
	return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
	}

	func TestAcceptError(t *testing.T) {
	handler := func(ls *localServer, ln Listener) {
	for {
	ln.(TCPListener).SetDeadline(time.Now().Add(5 time.Millisecond))
	c, err := ln.Accept()
	if perr := parseAcceptError(err); perr != nil {
	t.Error(perr)
	}
	if err != nil {
	if c != nil {
	t.Errorf("Accept returned non-nil interface %T(%v) with err != nil", c, c)
	}
	if !isTimeoutError(err) && !isTemporaryError(err) {
	return
	}
	continue
	}
	c.Close()
	}
	}
	ls, err := newLocalServer("tcp")
	if err != nil {
	t.Fatal(err)
	}
	if err := ls.buildup(handler); err != nil {
	ls.teardown()
	t.Fatal(err)
	}

	time.Sleep(100 * time.Millisecond)
	ls.teardown()
	}