func TestHostHandlers(t *testing.T) {
	for _, h := range handlers {
		http.Handle(h.pattern, stringHandler(h.msg))
	}
	ts := httptest.NewServer(nil)
	defer ts.Close()

	conn, err := net.Dial("tcp", ts.Listener.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	defer conn.Close()
	cc := httputil.NewClientConn(conn, nil)
	for _, vt := range vtests {
		var r *http.Response
		var req http.Request
		if req.URL, err = url.Parse(vt.url); err != nil {
			t.Errorf("cannot parse url: %v", err)
			continue
		}
		if err := cc.Write(&req); err != nil {
			t.Errorf("writing request: %v", err)
			continue
		}
		r, err := cc.Read(&req)
		if err != nil {
			t.Errorf("reading response: %v", err)
			continue
		}
		s := r.Header.Get("Result")
		if s != vt.expected {
			t.Errorf("Get(%q) = %q, want %q", vt.url, s, vt.expected)
		}
	}
}

func BenchmarkClientServer(b *testing.B) {
	b.StopTimer()
	ts := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(rw, "Hello world.\n")
	}))
	defer ts.Close()
	b.StartTimer()

	for i := 0; i < b.N; i++ {
		res, err := http.Get(ts.URL)
		if err != nil {
			b.Fatal("Get:", err)
		}
		all, err := ioutil.ReadAll(res.Body)
		if err != nil {
			b.Fatal("ReadAll:", err)
		}
		body := string(all)
		if body != "Hello world.\n" {
			b.Fatal("Got body:", body)
		}
	}

	b.StopTimer()
}

// TestHeadResponses verifies that responses to HEAD requests don't
// declare that they're chunking in their response headers, aren't
// allowed to produce output, and don't set a Content-Type since
// the real type of the body data cannot be inferred.
func TestHeadResponses(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, err := w.Write([]byte("Ignored body"))
		if err != http.ErrBodyNotAllowed {
			t.Errorf("on Write, expected ErrBodyNotAllowed, got %v", err)
		}

		// Also exercise the ReaderFrom path
		_, err = io.Copy(w, strings.NewReader("Ignored body"))
		if err != http.ErrBodyNotAllowed {
			t.Errorf("on Copy, expected ErrBodyNotAllowed, got %v", err)
		}
	}))
	defer ts.Close()
	res, err := http.Head(ts.URL)
	if err != nil {
		t.Error(err)
	}
	if len(res.TransferEncoding) > 0 {
		t.Errorf("expected no TransferEncoding; got %v", res.TransferEncoding)
	}
	ct := res.Header.Get("Content-Type")
	if ct != "" {
		t.Errorf("expected no Content-Type; got %s", ct)
	}
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Error(err)
	}
	if len(body) > 0 {
		t.Errorf("got unexpected body %q", string(body))
	}
}

func TestRequestBodyLimit(t *testing.T) {
	const limit = 1 << 20
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		r.Body = http.MaxBytesReader(w, r.Body, limit)
		n, err := io.Copy(ioutil.Discard, r.Body)
		if err == nil {
			t.Errorf("expected error from io.Copy")
		}
		if n != limit {
			t.Errorf("io.Copy = %d, want %d", n, limit)
		}
	}))
	defer ts.Close()

	nWritten := int64(0)
	req, _ := http.NewRequest("POST", ts.URL, io.LimitReader(countReader{neverEnding('a'), &nWritten}, limit*200))

	// Send the POST, but don't care it succeeds or not.  The
	// remote side is going to reply and then close the TCP
	// connection, and HTTP doesn't really define if that's
	// allowed or not.  Some HTTP clients will get the response
	// and some (like ours, currently) will complain that the
	// request write failed, without reading the response.
	//
	// But that's okay, since what we're really testing is that
	// the remote side hung up on us before we wrote too much.
	_, _ = http.DefaultClient.Do(req)

	if nWritten > limit*100 {
		t.Errorf("handler restricted the request body to %d bytes, but client managed to write %d",
			limit, nWritten)
	}
}

// TestClientWriteShutdown tests that if the client shuts down the write
// side of their TCP connection, the server doesn't send a 400 Bad Request.
func TestClientWriteShutdown(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
	defer ts.Close()
	conn, err := net.Dial("tcp", ts.Listener.Addr().String())
	if err != nil {
		t.Fatalf("Dial: %v", err)
	}
	err = conn.(*net.TCPConn).CloseWrite()
	if err != nil {
		t.Fatalf("Dial: %v", err)
	}
	donec := make(chan bool)
	go func() {
		defer close(donec)
		bs, err := ioutil.ReadAll(conn)
		if err != nil {
			t.Fatalf("ReadAll: %v", err)
		}
		got := string(bs)
		if got != "" {
			t.Errorf("read %q from server; want nothing", got)
		}
	}()
	select {
	case <-donec:
	case <-time.After(10 * time.Second):
		t.Fatalf("timeout")
	}
}

// TestContentLengthZero tests that for both an HTTP/1.0 and HTTP/1.1
// request (both keep-alive), when a Handler never writes any
// response, the net/http package adds a "Content-Length: 0" response
// header.
func TestContentLengthZero(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {}))
	defer ts.Close()

	for _, version := range []string{"HTTP/1.0", "HTTP/1.1"} {
		conn, err := net.Dial("tcp", ts.Listener.Addr().String())
		if err != nil {
			t.Fatalf("error dialing: %v", err)
		}
		_, err = fmt.Fprintf(conn, "GET / %v\r\nConnection: keep-alive\r\nHost: foo\r\n\r\n", version)
		if err != nil {
			t.Fatalf("error writing: %v", err)
		}
		req, _ := http.NewRequest("GET", "/", nil)
		res, err := http.ReadResponse(bufio.NewReader(conn), req)
		if err != nil {
			t.Fatalf("error reading response: %v", err)
		}
		if te := res.TransferEncoding; len(te) > 0 {
			t.Errorf("For version %q, Transfer-Encoding = %q; want none", version, te)
		}
		if cl := res.ContentLength; cl != 0 {
			t.Errorf("For version %q, Content-Length = %v; want 0", version, cl)
		}
		conn.Close()
	}
}

func testHandlerPanic(t *testing.T, withHijack bool) {
	// Unlike the other tests that set the log output to ioutil.Discard
	// to quiet the output, this test uses a pipe.  The pipe serves three
	// purposes:
	//
	//   1) The log.Print from the http server (generated by the caught
	//      panic) will go to the pipe instead of stderr, making the
	//      output quiet.
	//
	//   2) We read from the pipe to verify that the handler
	//      actually caught the panic and logged something.
	//
	//   3) The blocking Read call prevents this TestHandlerPanic
	//      function from exiting before the HTTP server handler
	//      finishes crashing. If this text function exited too
	//      early (and its defer log.SetOutput(os.Stderr) ran),
	//      then the crash output could spill into the next test.
	pr, pw := io.Pipe()
	log.SetOutput(pw)
	defer log.SetOutput(os.Stderr)

	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if withHijack {
			rwc, _, err := w.(http.Hijacker).Hijack()
			if err != nil {
				t.Logf("unexpected error: %v", err)
			}
			defer rwc.Close()
		}
		panic("intentional death for testing")
	}))
	defer ts.Close()

	// Do a blocking read on the log output pipe so its logging
	// doesn't bleed into the next test.  But wait only 5 seconds
	// for it.
	done := make(chan bool, 1)
	go func() {
		buf := make([]byte, 4<<10)
		_, err := pr.Read(buf)
		pr.Close()
		if err != nil {
			t.Fatal(err)
		}
		done <- true
	}()

	_, err := http.Get(ts.URL)
	if err == nil {
		t.Logf("expected an error")
	}

	select {
	case <-done:
		return
	case <-time.After(5 * time.Second):
		t.Fatal("expected server handler to log an error")
	}
}

// Tests that the server responds to the "Expect" request header
// correctly.
func TestServerExpect(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Note using r.FormValue("readbody") because for POST
		// requests that would read from r.Body, which we only
		// conditionally want to do.
		if strings.Contains(r.URL.RawQuery, "readbody=true") {
			ioutil.ReadAll(r.Body)
			w.Write([]byte("Hi"))
		} else {
			w.WriteHeader(http.StatusUnauthorized)
		}
	}))
	defer ts.Close()

	runTest := func(test serverExpectTest) {
		conn, err := net.Dial("tcp", ts.Listener.Addr().String())
		if err != nil {
			t.Fatalf("Dial: %v", err)
		}
		defer conn.Close()
		sendf := func(format string, args ...interface{}) {
			_, err := fmt.Fprintf(conn, format, args...)
			if err != nil {
				t.Fatalf("On test %#v, error writing %q: %v", test, format, err)
			}
		}
		go func() {
			sendf("POST /?readbody=%v HTTP/1.1\r\n"+
				"Connection: close\r\n"+
				"Content-Length: %d\r\n"+
				"Expect: %s\r\nHost: foo\r\n\r\n",
				test.readBody, test.contentLength, test.expectation)
			if test.contentLength > 0 && strings.ToLower(test.expectation) != "100-continue" {
				body := strings.Repeat("A", test.contentLength)
				sendf(body)
			}
		}()
		bufr := bufio.NewReader(conn)
		line, err := bufr.ReadString('\n')
		if err != nil {
			t.Fatalf("ReadString: %v", err)
		}
		if !strings.Contains(line, test.expectedResponse) {
			t.Errorf("for test %#v got first line=%q", test, line)
		}
	}

	for _, test := range serverExpectTests {
		runTest(test)
	}
}

func TestNoDate(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header()["Date"] = nil
	}))
	defer ts.Close()
	res, err := http.Get(ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	_, present := res.Header["Date"]
	if present {
		t.Fatalf("Expected no Date header; got %v", res.Header["Date"])
	}
}

func TestTimeoutHandler(t *testing.T) {
	sendHi := make(chan bool, 1)
	writeErrors := make(chan error, 1)
	sayHi := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		<-sendHi
		_, werr := w.Write([]byte("hi"))
		writeErrors <- werr
	})
	timeout := make(chan time.Time, 1) // write to this to force timeouts
	ts := httptest.NewServer(NewTestTimeoutHandler(sayHi, timeout))
	defer ts.Close()

	// Succeed without timing out:
	sendHi <- true
	res, err := http.Get(ts.URL)
	if err != nil {
		t.Error(err)
	}
	if g, e := res.StatusCode, http.StatusOK; g != e {
		t.Errorf("got res.StatusCode %d; expected %d", g, e)
	}
	body, _ := ioutil.ReadAll(res.Body)
	if g, e := string(body), "hi"; g != e {
		t.Errorf("got body %q; expected %q", g, e)
	}
	if g := <-writeErrors; g != nil {
		t.Errorf("got unexpected Write error on first request: %v", g)
	}

	// Times out:
	timeout <- time.Time{}
	res, err = http.Get(ts.URL)
	if err != nil {
		t.Error(err)
	}
	if g, e := res.StatusCode, http.StatusServiceUnavailable; g != e {
		t.Errorf("got res.StatusCode %d; expected %d", g, e)
	}
	body, _ = ioutil.ReadAll(res.Body)
	if !strings.Contains(string(body), "<title>Timeout</title>") {
		t.Errorf("expected timeout body; got %q", string(body))
	}

	// Now make the previously-timed out handler speak again,
	// which verifies the panic is handled:
	sendHi <- true
	if g, e := <-writeErrors, http.ErrHandlerTimeout; g != e {
		t.Errorf("expected Write error of %v; got %v", e, g)
	}
}

func TestSetsRemoteAddr(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "%s", r.RemoteAddr)
	}))
	defer ts.Close()

	res, err := http.Get(ts.URL)
	if err != nil {
		t.Fatalf("Get error: %v", err)
	}
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Fatalf("ReadAll error: %v", err)
	}
	ip := string(body)
	if !strings.HasPrefix(ip, "127.0.0.1:") && !strings.HasPrefix(ip, "[::1]:") {
		t.Fatalf("Expected local addr; got %q", ip)
	}
}

func testTcpConnectionCloses(t *testing.T, req string, h http.Handler) {
	s := httptest.NewServer(h)
	defer s.Close()

	conn, err := net.Dial("tcp", s.Listener.Addr().String())
	if err != nil {
		t.Fatal("dial error:", err)
	}
	defer conn.Close()

	_, err = fmt.Fprint(conn, req)
	if err != nil {
		t.Fatal("print error:", err)
	}

	r := bufio.NewReader(conn)
	res, err := http.ReadResponse(r, &http.Request{Method: "GET"})
	if err != nil {
		t.Fatal("ReadResponse error:", err)
	}

	didReadAll := make(chan bool, 1)
	go func() {
		select {
		case <-time.After(5 * time.Second):
			t.Error("body not closed after 5s")
			return
		case <-didReadAll:
		}
	}()

	_, err = ioutil.ReadAll(r)
	if err != nil {
		t.Fatal("read error:", err)
	}
	didReadAll <- true

	if !res.Close {
		t.Errorf("Response.Close = false; want true")
	}
}

func TestRequestLimit(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		t.Fatalf("didn't expect to get request in Handler")
	}))
	defer ts.Close()
	req, _ := http.NewRequest("GET", ts.URL, nil)
	var bytesPerHeader = len("header12345: val12345\r\n")
	for i := 0; i < ((http.DefaultMaxHeaderBytes+4096)/bytesPerHeader)+1; i++ {
		req.Header.Set(fmt.Sprintf("header%05d", i), fmt.Sprintf("val%05d", i))
	}
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		// Some HTTP clients may fail on this undefined behavior (server replying and
		// closing the connection while the request is still being written), but
		// we do support it (at least currently), so we expect a response below.
		t.Fatalf("Do: %v", err)
	}
	if res.StatusCode != 413 {
		t.Fatalf("expected 413 response status; got: %d %s", res.StatusCode, res.Status)
	}
}

func TestStripPrefix(t *testing.T) {
	h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("X-Path", r.URL.Path)
	})
	ts := httptest.NewServer(http.StripPrefix("/foo", h))
	defer ts.Close()

	res, err := http.Get(ts.URL + "/foo/bar")
	if err != nil {
		t.Fatal(err)
	}
	if g, e := res.Header.Get("X-Path"), "/bar"; g != e {
		t.Errorf("test 1: got %s, want %s", g, e)
	}

	res, err = http.Get(ts.URL + "/bar")
	if err != nil {
		t.Fatal(err)
	}
	if g, e := res.StatusCode, 404; g != e {
		t.Errorf("test 2: got status %v, want %v", g, e)
	}
}

// TestZeroLengthPostAndResponse exercises an optimization done by the Transport:
// when there is no body (either because the method doesn't permit a body, or an
// explicit Content-Length of zero is present), then the transport can re-use the
// connection immediately. But when it re-uses the connection, it typically closes
// the previous request's body, which is not optimal for zero-lengthed bodies,
// as the client would then see http.ErrBodyReadAfterClose and not 0, io.EOF.
func TestZeroLengthPostAndResponse(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
		all, err := ioutil.ReadAll(r.Body)
		if err != nil {
			t.Fatalf("handler ReadAll: %v", err)
		}
		if len(all) != 0 {
			t.Errorf("handler got %d bytes; expected 0", len(all))
		}
		rw.Header().Set("Content-Length", "0")
	}))
	defer ts.Close()

	req, err := http.NewRequest("POST", ts.URL, strings.NewReader(""))
	if err != nil {
		t.Fatal(err)
	}
	req.ContentLength = 0

	var resp [5]*http.Response
	for i := range resp {
		resp[i], err = http.DefaultClient.Do(req)
		if err != nil {
			t.Fatalf("client post #%d: %v", i, err)
		}
	}

	for i := range resp {
		all, err := ioutil.ReadAll(resp[i].Body)
		if err != nil {
			t.Fatalf("req #%d: client ReadAll: %v", i, err)
		}
		if len(all) != 0 {
			t.Errorf("req #%d: client got %d bytes; expected 0", i, len(all))
		}
	}
}

// Test304Responses verifies that 304s don't declare that they're
// chunking in their response headers and aren't allowed to produce
// output.
func Test304Responses(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotModified)
		_, err := w.Write([]byte("illegal body"))
		if err != http.ErrBodyNotAllowed {
			t.Errorf("on Write, expected ErrBodyNotAllowed, got %v", err)
		}
	}))
	defer ts.Close()
	res, err := http.Get(ts.URL)
	if err != nil {
		t.Error(err)
	}
	if len(res.TransferEncoding) > 0 {
		t.Errorf("expected no TransferEncoding; got %v", res.TransferEncoding)
	}
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Error(err)
	}
	if len(body) > 0 {
		t.Errorf("got unexpected body %q", string(body))
	}
}

func TestChunkedResponseHeaders(t *testing.T) {
	log.SetOutput(ioutil.Discard) // is noisy otherwise
	defer log.SetOutput(os.Stderr)

	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Length", "intentional gibberish") // we check that this is deleted
		fmt.Fprintf(w, "I am a chunked response.")
	}))
	defer ts.Close()

	res, err := http.Get(ts.URL)
	if err != nil {
		t.Fatalf("Get error: %v", err)
	}
	if g, e := res.ContentLength, int64(-1); g != e {
		t.Errorf("expected ContentLength of %d; got %d", e, g)
	}
	if g, e := res.TransferEncoding, []string{"chunked"}; !reflect.DeepEqual(g, e) {
		t.Errorf("expected TransferEncoding of %v; got %v", e, g)
	}
	if _, haveCL := res.Header["Content-Length"]; haveCL {
		t.Errorf("Unexpected Content-Length")
	}
}

// TestIdentityResponse verifies that a handler can unset
func TestIdentityResponse(t *testing.T) {
	handler := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		rw.Header().Set("Content-Length", "3")
		rw.Header().Set("Transfer-Encoding", req.FormValue("te"))
		switch {
		case req.FormValue("overwrite") == "1":
			_, err := rw.Write([]byte("foo TOO LONG"))
			if err != http.ErrContentLength {
				t.Errorf("expected ErrContentLength; got %v", err)
			}
		case req.FormValue("underwrite") == "1":
			rw.Header().Set("Content-Length", "500")
			rw.Write([]byte("too short"))
		default:
			rw.Write([]byte("foo"))
		}
	})

	ts := httptest.NewServer(handler)
	defer ts.Close()

	// Note: this relies on the assumption (which is true) that
	// Get sends HTTP/1.1 or greater requests.  Otherwise the
	// server wouldn't have the choice to send back chunked
	// responses.
	for _, te := range []string{"", "identity"} {
		url := ts.URL + "/?te=" + te
		res, err := http.Get(url)
		if err != nil {
			t.Fatalf("error with Get of %s: %v", url, err)
		}
		if cl, expected := res.ContentLength, int64(3); cl != expected {
			t.Errorf("for %s expected res.ContentLength of %d; got %d", url, expected, cl)
		}
		if cl, expected := res.Header.Get("Content-Length"), "3"; cl != expected {
			t.Errorf("for %s expected Content-Length header of %q; got %q", url, expected, cl)
		}
		if tl, expected := len(res.TransferEncoding), 0; tl != expected {
			t.Errorf("for %s expected len(res.TransferEncoding) of %d; got %d (%v)",
				url, expected, tl, res.TransferEncoding)
		}
		res.Body.Close()
	}

	// Verify that ErrContentLength is returned
	url := ts.URL + "/?overwrite=1"
	_, err := http.Get(url)
	if err != nil {
		t.Fatalf("error with Get of %s: %v", url, err)
	}
	// Verify that the connection is closed when the declared Content-Length
	// is larger than what the handler wrote.
	conn, err := net.Dial("tcp", ts.Listener.Addr().String())
	if err != nil {
		t.Fatalf("error dialing: %v", err)
	}
	_, err = conn.Write([]byte("GET /?underwrite=1 HTTP/1.1\r\nHost: foo\r\n\r\n"))
	if err != nil {
		t.Fatalf("error writing: %v", err)
	}

	// The ReadAll will hang for a failing test, so use a Timer to
	// fail explicitly.
	goTimeout(t, 2*time.Second, func() {
		got, _ := ioutil.ReadAll(conn)
		expectedSuffix := "\r\n\r\ntoo short"
		if !strings.HasSuffix(string(got), expectedSuffix) {
			t.Errorf("Expected output to end with %q; got response body %q",
				expectedSuffix, string(got))
		}
	})
}