diff --git a/README.md b/README.md index 20e391f..2469694 100644 --- a/README.md +++ b/README.md @@ -27,7 +27,7 @@ package API is stable. ### Protocol Compliance The Gorilla WebSocket package passes the server tests in the [Autobahn Test -Suite](http://autobahn.ws/testsuite) using the application in the [examples/autobahn +Suite](https://github.com/crossbario/autobahn-testsuite) using the application in the [examples/autobahn subdirectory](https://github.com/gorilla/websocket/tree/master/examples/autobahn). ### Gorilla WebSocket compared with other packages diff --git a/client.go b/client.go index 34ca595..87c71ac 100644 --- a/client.go +++ b/client.go @@ -71,7 +71,7 @@ type Dialer struct { // HandshakeTimeout specifies the duration for the handshake to complete. HandshakeTimeout time.Duration - // ReadBufferSize and WriteBufferSize specify I/O buffer sizes. If a buffer + // ReadBufferSize and WriteBufferSize specify I/O buffer sizes in bytes. If a buffer // size is zero, then a useful default size is used. The I/O buffer sizes // do not limit the size of the messages that can be sent or received. ReadBufferSize, WriteBufferSize int @@ -144,7 +144,7 @@ var nilDialer = *DefaultDialer // Use the response.Header to get the selected subprotocol // (Sec-WebSocket-Protocol) and cookies (Set-Cookie). // -// The context will be used in the request and in the Dialer +// The context will be used in the request and in the Dialer. // // If the WebSocket handshake fails, ErrBadHandshake is returned along with a // non-nil *http.Response so that callers can handle redirects, authentication, diff --git a/client_server_test.go b/client_server_test.go index bacd060..e4079ae 100644 --- a/client_server_test.go +++ b/client_server_test.go @@ -11,8 +11,10 @@ import ( "crypto/x509" "encoding/base64" "encoding/binary" + "fmt" "io" "io/ioutil" + "log" "net" "net/http" "net/http/cookiejar" @@ -51,15 +53,10 @@ type cstHandler struct { cstHandlerConfig } -var cstDialerWithoutHandshakeTimeout = Dialer{ - Subprotocols: []string{"p1", "p2"}, - ReadBufferSize: 1024, - WriteBufferSize: 1024, -} - type cstServer struct { *httptest.Server URL string + t *testing.T } const ( @@ -341,10 +338,7 @@ func TestDialCookieJar(t *testing.T) { sendRecv(t, ws) } -func TestDialTLS(t *testing.T) { - s := newTLSServer(t, cstHandlerConfig{}) - defer s.Close() - +func rootCAs(t *testing.T, s *httptest.Server) *x509.CertPool { certs := x509.NewCertPool() for _, c := range s.TLS.Certificates { roots, err := x509.ParseCertificates(c.Certificate[len(c.Certificate)-1]) @@ -355,35 +349,15 @@ func TestDialTLS(t *testing.T) { certs.AddCert(root) } } - - d := cstDialer - d.TLSClientConfig = &tls.Config{RootCAs: certs} - ws, _, err := d.Dial(s.URL, nil) - if err != nil { - t.Fatalf("Dial: %v", err) - } - defer ws.Close() - sendRecv(t, ws) + return certs } -func xTestDialTLSBadCert(t *testing.T) { - // This test is deactivated because of noisy logging from the net/http package. - s := newTLSServer(t, cstHandlerConfig{}) - defer s.Close() - - ws, _, err := cstDialer.Dial(s.URL, nil) - if err == nil { - ws.Close() - t.Fatalf("Dial: nil") - } -} - -func TestDialTLSNoVerify(t *testing.T) { +func TestDialTLS(t *testing.T) { s := newTLSServer(t, cstHandlerConfig{}) defer s.Close() d := cstDialer - d.TLSClientConfig = &tls.Config{InsecureSkipVerify: true} + d.TLSClientConfig = &tls.Config{RootCAs: rootCAs(t, s.Server)} ws, _, err := d.Dial(s.URL, nil) if err != nil { t.Fatalf("Dial: %v", err) @@ -468,7 +442,8 @@ func TestHandshakeTimeoutInContext(t *testing.T) { s := newServer(t, cstHandlerConfig{}) defer s.Close() - d := cstDialerWithoutHandshakeTimeout + d := cstDialer + d.HandshakeTimeout = 0 d.NetDialContext = func(ctx context.Context, n, a string) (net.Conn, error) { netDialer := &net.Dialer{} c, err := netDialer.DialContext(ctx, n, a) @@ -619,33 +594,195 @@ func TestRespOnBadHandshake(t *testing.T) { } } -// TestHostHeader confirms that the host header provided in the call to Dial is -// sent to the server. -func TestHostHeader(t *testing.T) { - s := newServer(t, cstHandlerConfig{}) - defer s.Close() +type testLogWriter struct { + t *testing.T +} - specifiedHost := make(chan string, 1) - origHandler := s.Server.Config.Handler +func (w testLogWriter) Write(p []byte) (int, error) { + w.t.Logf("%s", p) + return len(p), nil +} - // Capture the request Host header. - s.Server.Config.Handler = http.HandlerFunc( - func(w http.ResponseWriter, r *http.Request) { - specifiedHost <- r.Host - origHandler.ServeHTTP(w, r) - }) +// TestHost tests handling of host names and confirms that it matches net/http. +func TestHost(t *testing.T) { - ws, _, err := cstDialer.Dial(s.URL, http.Header{"Host": {"testhost"}}) - if err != nil { - t.Fatalf("Dial: %v", err) - } - defer ws.Close() + upgrader := Upgrader{} + handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + if IsWebSocketUpgrade(r) { + c, err := upgrader.Upgrade(w, r, http.Header{"X-Test-Host": {r.Host}}) + if err != nil { + t.Fatal(err) + } + c.Close() + } else { + w.Header().Set("X-Test-Host", r.Host) + } + }) - if gotHost := <-specifiedHost; gotHost != "testhost" { - t.Fatalf("gotHost = %q, want \"testhost\"", gotHost) + server := httptest.NewServer(handler) + defer server.Close() + + tlsServer := httptest.NewTLSServer(handler) + defer tlsServer.Close() + + addrs := map[*httptest.Server]string{server: server.Listener.Addr().String(), tlsServer: tlsServer.Listener.Addr().String()} + wsProtos := map[*httptest.Server]string{server: "ws://", tlsServer: "wss://"} + httpProtos := map[*httptest.Server]string{server: "http://", tlsServer: "https://"} + + // Avoid log noise from net/http server by logging to testing.T + server.Config.ErrorLog = log.New(testLogWriter{t}, "", 0) + tlsServer.Config.ErrorLog = server.Config.ErrorLog + + cas := rootCAs(t, tlsServer) + + tests := []struct { + fail bool // true if dial / get should fail + server *httptest.Server // server to use + url string // host for request URI + header string // optional request host header + tls string // optiona host for tls ServerName + wantAddr string // expected host for dial + wantHeader string // expected request header on server + insecureSkipVerify bool + }{ + { + server: server, + url: addrs[server], + wantAddr: addrs[server], + wantHeader: addrs[server], + }, + { + server: tlsServer, + url: addrs[tlsServer], + wantAddr: addrs[tlsServer], + wantHeader: addrs[tlsServer], + }, + + { + server: server, + url: addrs[server], + header: "badhost.com", + wantAddr: addrs[server], + wantHeader: "badhost.com", + }, + { + server: tlsServer, + url: addrs[tlsServer], + header: "badhost.com", + wantAddr: addrs[tlsServer], + wantHeader: "badhost.com", + }, + + { + server: server, + url: "example.com", + header: "badhost.com", + wantAddr: "example.com:80", + wantHeader: "badhost.com", + }, + { + server: tlsServer, + url: "example.com", + header: "badhost.com", + wantAddr: "example.com:443", + wantHeader: "badhost.com", + }, + + { + server: server, + url: "badhost.com", + header: "example.com", + wantAddr: "badhost.com:80", + wantHeader: "example.com", + }, + { + fail: true, + server: tlsServer, + url: "badhost.com", + header: "example.com", + wantAddr: "badhost.com:443", + }, + { + server: tlsServer, + url: "badhost.com", + insecureSkipVerify: true, + wantAddr: "badhost.com:443", + wantHeader: "badhost.com", + }, + { + server: tlsServer, + url: "badhost.com", + tls: "example.com", + wantAddr: "badhost.com:443", + wantHeader: "badhost.com", + }, } - sendRecv(t, ws) + for i, tt := range tests { + + tls := &tls.Config{ + RootCAs: cas, + ServerName: tt.tls, + InsecureSkipVerify: tt.insecureSkipVerify, + } + + var gotAddr string + dialer := Dialer{ + NetDial: func(network, addr string) (net.Conn, error) { + gotAddr = addr + return net.Dial(network, addrs[tt.server]) + }, + TLSClientConfig: tls, + } + + // Test websocket dial + + h := http.Header{} + if tt.header != "" { + h.Set("Host", tt.header) + } + c, resp, err := dialer.Dial(wsProtos[tt.server]+tt.url+"/", h) + if err == nil { + c.Close() + } + + check := func(protos map[*httptest.Server]string) { + name := fmt.Sprintf("%d: %s%s/ header[Host]=%q, tls.ServerName=%q", i+1, protos[tt.server], tt.url, tt.header, tt.tls) + if gotAddr != tt.wantAddr { + t.Errorf("%s: got addr %s, want %s", name, gotAddr, tt.wantAddr) + } + switch { + case tt.fail && err == nil: + t.Errorf("%s: unexpected success", name) + case !tt.fail && err != nil: + t.Errorf("%s: unexpected error %v", name, err) + case !tt.fail && err == nil: + if gotHost := resp.Header.Get("X-Test-Host"); gotHost != tt.wantHeader { + t.Errorf("%s: got host %s, want %s", name, gotHost, tt.wantHeader) + } + } + } + + check(wsProtos) + + // Confirm that net/http has same result + + transport := &http.Transport{ + Dial: dialer.NetDial, + TLSClientConfig: dialer.TLSClientConfig, + } + req, _ := http.NewRequest("GET", httpProtos[tt.server]+tt.url+"/", nil) + if tt.header != "" { + req.Host = tt.header + } + client := &http.Client{Transport: transport} + resp, err = client.Do(req) + if err == nil { + resp.Body.Close() + } + transport.CloseIdleConnections() + check(httpProtos) + } } func TestDialCompression(t *testing.T) { @@ -785,19 +922,8 @@ func TestTracingDialWithContext(t *testing.T) { s := newTLSServer(t, cstHandlerConfig{}) defer s.Close() - certs := x509.NewCertPool() - for _, c := range s.TLS.Certificates { - roots, err := x509.ParseCertificates(c.Certificate[len(c.Certificate)-1]) - if err != nil { - t.Fatalf("error parsing server's root cert: %v", err) - } - for _, root := range roots { - certs.AddCert(root) - } - } - d := cstDialer - d.TLSClientConfig = &tls.Config{RootCAs: certs} + d.TLSClientConfig = &tls.Config{RootCAs: rootCAs(t, s.Server)} ws, _, err := d.DialContext(ctx, s.URL, nil) if err != nil { @@ -835,19 +961,8 @@ func TestEmptyTracingDialWithContext(t *testing.T) { s := newTLSServer(t, cstHandlerConfig{}) defer s.Close() - certs := x509.NewCertPool() - for _, c := range s.TLS.Certificates { - roots, err := x509.ParseCertificates(c.Certificate[len(c.Certificate)-1]) - if err != nil { - t.Fatalf("error parsing server's root cert: %v", err) - } - for _, root := range roots { - certs.AddCert(root) - } - } - d := cstDialer - d.TLSClientConfig = &tls.Config{RootCAs: certs} + d.TLSClientConfig = &tls.Config{RootCAs: rootCAs(t, s.Server)} ws, _, err := d.DialContext(ctx, s.URL, nil) if err != nil { diff --git a/conn.go b/conn.go index 7524521..62d55b1 100644 --- a/conn.go +++ b/conn.go @@ -453,7 +453,8 @@ func (c *Conn) WriteControl(messageType int, data []byte, deadline time.Time) er return err } -func (c *Conn) prepWrite(messageType int) error { +// beginMessage prepares a connection and message writer for a new message. +func (c *Conn) beginMessage(mw *messageWriter, messageType int) error { // Close previous writer if not already closed by the application. It's // probably better to return an error in this situation, but we cannot // change this without breaking existing applications. @@ -473,6 +474,10 @@ func (c *Conn) prepWrite(messageType int) error { return err } + mw.c = c + mw.frameType = messageType + mw.pos = maxFrameHeaderSize + if c.writeBuf == nil { wpd, ok := c.writePool.Get().(writePoolData) if ok { @@ -493,16 +498,11 @@ func (c *Conn) prepWrite(messageType int) error { // All message types (TextMessage, BinaryMessage, CloseMessage, PingMessage and // PongMessage) are supported. func (c *Conn) NextWriter(messageType int) (io.WriteCloser, error) { - if err := c.prepWrite(messageType); err != nil { + var mw messageWriter + if err := c.beginMessage(&mw, messageType); err != nil { return nil, err } - - mw := &messageWriter{ - c: c, - frameType: messageType, - pos: maxFrameHeaderSize, - } - c.writer = mw + c.writer = &mw if c.newCompressionWriter != nil && c.enableWriteCompression && isData(messageType) { w := c.newCompressionWriter(c.writer, c.compressionLevel) mw.compress = true @@ -519,10 +519,16 @@ type messageWriter struct { err error } -func (w *messageWriter) fatal(err error) error { +func (w *messageWriter) endMessage(err error) error { if w.err != nil { - w.err = err - w.c.writer = nil + return err + } + c := w.c + w.err = err + c.writer = nil + if c.writePool != nil { + c.writePool.Put(writePoolData{buf: c.writeBuf}) + c.writeBuf = nil } return err } @@ -536,7 +542,7 @@ func (w *messageWriter) flushFrame(final bool, extra []byte) error { // Check for invalid control frames. if isControl(w.frameType) && (!final || length > maxControlFramePayloadSize) { - return w.fatal(errInvalidControlFrame) + return w.endMessage(errInvalidControlFrame) } b0 := byte(w.frameType) @@ -581,7 +587,7 @@ func (w *messageWriter) flushFrame(final bool, extra []byte) error { copy(c.writeBuf[maxFrameHeaderSize-4:], key[:]) maskBytes(key, 0, c.writeBuf[maxFrameHeaderSize:w.pos]) if len(extra) > 0 { - return c.writeFatal(errors.New("websocket: internal error, extra used in client mode")) + return w.endMessage(c.writeFatal(errors.New("websocket: internal error, extra used in client mode"))) } } @@ -602,15 +608,11 @@ func (w *messageWriter) flushFrame(final bool, extra []byte) error { c.isWriting = false if err != nil { - return w.fatal(err) + return w.endMessage(err) } if final { - c.writer = nil - if c.writePool != nil { - c.writePool.Put(writePoolData{buf: c.writeBuf}) - c.writeBuf = nil - } + w.endMessage(errWriteClosed) return nil } @@ -711,7 +713,6 @@ func (w *messageWriter) Close() error { if err := w.flushFrame(true, nil); err != nil { return err } - w.err = errWriteClosed return nil } @@ -744,10 +745,10 @@ func (c *Conn) WriteMessage(messageType int, data []byte) error { if c.isServer && (c.newCompressionWriter == nil || !c.enableWriteCompression) { // Fast path with no allocations and single frame. - if err := c.prepWrite(messageType); err != nil { + var mw messageWriter + if err := c.beginMessage(&mw, messageType); err != nil { return err } - mw := messageWriter{c: c, frameType: messageType, pos: maxFrameHeaderSize} n := copy(c.writeBuf[mw.pos:], data) mw.pos += n data = data[n:] @@ -1043,7 +1044,7 @@ func (c *Conn) SetReadDeadline(t time.Time) error { return c.conn.SetReadDeadline(t) } -// SetReadLimit sets the maximum size for a message read from the peer. If a +// SetReadLimit sets the maximum size in bytes for a message read from the peer. If a // message exceeds the limit, the connection sends a close message to the peer // and returns ErrReadLimit to the application. func (c *Conn) SetReadLimit(limit int64) { diff --git a/conn_test.go b/conn_test.go index cd08ca8..7be8a4f 100644 --- a/conn_test.go +++ b/conn_test.go @@ -227,11 +227,16 @@ func (p *simpleBufferPool) Put(v interface{}) { } func TestWriteBufferPool(t *testing.T) { + const message = "Now is the time for all good people to come to the aid of the party." + var buf bytes.Buffer var pool simpleBufferPool - wc := newConn(fakeNetConn{Writer: &buf}, true, 1024, 1024, &pool, nil, nil) rc := newTestConn(&buf, nil, false) + // Specify writeBufferSize smaller than message size to ensure that pooling + // works with fragmented messages. + wc := newConn(fakeNetConn{Writer: &buf}, true, 1024, len(message)-1, &pool, nil, nil) + if wc.writeBuf != nil { t.Fatal("writeBuf not nil after create") } @@ -249,8 +254,6 @@ func TestWriteBufferPool(t *testing.T) { writeBufAddr := &wc.writeBuf[0] - const message = "Hello World!" - if _, err := io.WriteString(w, message); err != nil { t.Fatalf("io.WriteString(w, message) returned %v", err) } @@ -300,6 +303,7 @@ func TestWriteBufferPool(t *testing.T) { } } +// TestWriteBufferPoolSync ensures that *sync.Pool works as a buffer pool. func TestWriteBufferPoolSync(t *testing.T) { var buf bytes.Buffer var pool sync.Pool @@ -321,6 +325,56 @@ func TestWriteBufferPoolSync(t *testing.T) { } } +// errorWriter is an io.Writer than returns an error on all writes. +type errorWriter struct{} + +func (ew errorWriter) Write(p []byte) (int, error) { return 0, errors.New("Error!") } + +// TestWriteBufferPoolError ensures that buffer is returned to pool after error +// on write. +func TestWriteBufferPoolError(t *testing.T) { + + // Part 1: Test NextWriter/Write/Close + + var pool simpleBufferPool + wc := newConn(fakeNetConn{Writer: errorWriter{}}, true, 1024, 1024, &pool, nil, nil) + + w, err := wc.NextWriter(TextMessage) + if err != nil { + t.Fatalf("wc.NextWriter() returned %v", err) + } + + if wc.writeBuf == nil { + t.Fatal("writeBuf is nil after NextWriter") + } + + writeBufAddr := &wc.writeBuf[0] + + if _, err := io.WriteString(w, "Hello"); err != nil { + t.Fatalf("io.WriteString(w, message) returned %v", err) + } + + if err := w.Close(); err == nil { + t.Fatalf("w.Close() did not return error") + } + + if wpd, ok := pool.v.(writePoolData); !ok || len(wpd.buf) == 0 || &wpd.buf[0] != writeBufAddr { + t.Fatal("writeBuf not returned to pool") + } + + // Part 2: Test WriteMessage + + wc = newConn(fakeNetConn{Writer: errorWriter{}}, true, 1024, 1024, &pool, nil, nil) + + if err := wc.WriteMessage(TextMessage, []byte("Hello")); err == nil { + t.Fatalf("wc.WriteMessage did not return error") + } + + if wpd, ok := pool.v.(writePoolData); !ok || len(wpd.buf) == 0 || &wpd.buf[0] != writeBufAddr { + t.Fatal("writeBuf not returned to pool") + } +} + func TestCloseFrameBeforeFinalMessageFrame(t *testing.T) { const bufSize = 512 diff --git a/examples/autobahn/README.md b/examples/autobahn/README.md index 075ac15..dde8525 100644 --- a/examples/autobahn/README.md +++ b/examples/autobahn/README.md @@ -1,6 +1,6 @@ # Test Server -This package contains a server for the [Autobahn WebSockets Test Suite](http://autobahn.ws/testsuite). +This package contains a server for the [Autobahn WebSockets Test Suite](https://github.com/crossbario/autobahn-testsuite). To test the server, run diff --git a/server.go b/server.go index 93f134f..4bd0539 100644 --- a/server.go +++ b/server.go @@ -28,7 +28,7 @@ type Upgrader struct { // HandshakeTimeout specifies the duration for the handshake to complete. HandshakeTimeout time.Duration - // ReadBufferSize and WriteBufferSize specify I/O buffer sizes. If a buffer + // ReadBufferSize and WriteBufferSize specify I/O buffer sizes in bytes. If a buffer // size is zero, then buffers allocated by the HTTP server are used. The // I/O buffer sizes do not limit the size of the messages that can be sent // or received. diff --git a/util.go b/util.go index 354001e..7bf2f66 100644 --- a/util.go +++ b/util.go @@ -31,68 +31,113 @@ func generateChallengeKey() (string, error) { return base64.StdEncoding.EncodeToString(p), nil } -// Octet types from RFC 2616. -var octetTypes [256]byte - -const ( - isTokenOctet = 1 << iota - isSpaceOctet -) - -func init() { - // From RFC 2616 - // - // OCTET = - // CHAR = - // CTL = - // CR = - // LF = - // SP = - // HT = - // <"> = - // CRLF = CR LF - // LWS = [CRLF] 1*( SP | HT ) - // TEXT = - // separators = "(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\" | <"> - // | "/" | "[" | "]" | "?" | "=" | "{" | "}" | SP | HT - // token = 1* - // qdtext = > - - for c := 0; c < 256; c++ { - var t byte - isCtl := c <= 31 || c == 127 - isChar := 0 <= c && c <= 127 - isSeparator := strings.IndexRune(" \t\"(),/:;<=>?@[]\\{}", rune(c)) >= 0 - if strings.IndexRune(" \t\r\n", rune(c)) >= 0 { - t |= isSpaceOctet - } - if isChar && !isCtl && !isSeparator { - t |= isTokenOctet - } - octetTypes[c] = t - } +// Token octets per RFC 2616. +var isTokenOctet = [256]bool{ + '!': true, + '#': true, + '$': true, + '%': true, + '&': true, + '\'': true, + '*': true, + '+': true, + '-': true, + '.': true, + '0': true, + '1': true, + '2': true, + '3': true, + '4': true, + '5': true, + '6': true, + '7': true, + '8': true, + '9': true, + 'A': true, + 'B': true, + 'C': true, + 'D': true, + 'E': true, + 'F': true, + 'G': true, + 'H': true, + 'I': true, + 'J': true, + 'K': true, + 'L': true, + 'M': true, + 'N': true, + 'O': true, + 'P': true, + 'Q': true, + 'R': true, + 'S': true, + 'T': true, + 'U': true, + 'W': true, + 'V': true, + 'X': true, + 'Y': true, + 'Z': true, + '^': true, + '_': true, + '`': true, + 'a': true, + 'b': true, + 'c': true, + 'd': true, + 'e': true, + 'f': true, + 'g': true, + 'h': true, + 'i': true, + 'j': true, + 'k': true, + 'l': true, + 'm': true, + 'n': true, + 'o': true, + 'p': true, + 'q': true, + 'r': true, + 's': true, + 't': true, + 'u': true, + 'v': true, + 'w': true, + 'x': true, + 'y': true, + 'z': true, + '|': true, + '~': true, } +// skipSpace returns a slice of the string s with all leading RFC 2616 linear +// whitespace removed. func skipSpace(s string) (rest string) { i := 0 for ; i < len(s); i++ { - if octetTypes[s[i]]&isSpaceOctet == 0 { + if b := s[i]; b != ' ' && b != '\t' { break } } return s[i:] } +// nextToken returns the leading RFC 2616 token of s and the string following +// the token. func nextToken(s string) (token, rest string) { i := 0 for ; i < len(s); i++ { - if octetTypes[s[i]]&isTokenOctet == 0 { + if !isTokenOctet[s[i]] { break } } return s[:i], s[i:] } +// nextTokenOrQuoted returns the leading token or quoted string per RFC 2616 +// and the string following the token or quoted string. func nextTokenOrQuoted(s string) (value string, rest string) { if !strings.HasPrefix(s, "\"") { return nextToken(s) @@ -128,7 +173,8 @@ func nextTokenOrQuoted(s string) (value string, rest string) { return "", "" } -// equalASCIIFold returns true if s is equal to t with ASCII case folding. +// equalASCIIFold returns true if s is equal to t with ASCII case folding as +// defined in RFC 4790. func equalASCIIFold(s, t string) bool { for s != "" && t != "" { sr, size := utf8.DecodeRuneInString(s) diff --git a/util_test.go b/util_test.go index 6e15965..af710ba 100644 --- a/util_test.go +++ b/util_test.go @@ -17,6 +17,7 @@ var equalASCIIFoldTests = []struct { {"WebSocket", "websocket", true}, {"websocket", "WebSocket", true}, {"Öyster", "öyster", false}, + {"WebSocket", "WetSocket", false}, } func TestEqualASCIIFold(t *testing.T) {