github.com/varialus/godfly@v0.0.0-20130904042352-1934f9f095ab/src/pkg/net/http/transport_test.go

// Copyright 2011 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.

// Tests for transport.go

package http_test

import (
	"bufio"
	"bytes"
	"compress/gzip"
	"crypto/rand"
	"fmt"
	"io"
	"io/ioutil"
	"net"
	"net/http"
	. "net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"
)

// TODO: test 5 pipelined requests with responses: 1) OK, 2) OK, Connection: Close
//       and then verify that the final 2 responses get errors back.

// hostPortHandler writes back the client's "host:port".
var hostPortHandler = HandlerFunc(func(w ResponseWriter, r *Request) {
	if r.FormValue("close") == "true" {
		w.Header().Set("Connection", "close")
	}
	w.Write([]byte(r.RemoteAddr))
})

// testCloseConn is a net.Conn tracked by a testConnSet.
type testCloseConn struct {
	net.Conn
	set *testConnSet
}

func (c *testCloseConn) Close() error {
	c.set.remove(c)
	return c.Conn.Close()
}

// testConnSet tracks a set of TCP connections and whether they've
// been closed.
type testConnSet struct {
	t      *testing.T
	closed map[net.Conn]bool
	list   []net.Conn // in order created
	mutex  sync.Mutex
}

func (tcs *testConnSet) insert(c net.Conn) {
	tcs.mutex.Lock()
	defer tcs.mutex.Unlock()
	tcs.closed[c] = false
	tcs.list = append(tcs.list, c)
}

func (tcs *testConnSet) remove(c net.Conn) {
	tcs.mutex.Lock()
	defer tcs.mutex.Unlock()
	tcs.closed[c] = true
}

// some tests use this to manage raw tcp connections for later inspection
func makeTestDial(t *testing.T) (*testConnSet, func(n, addr string) (net.Conn, error)) {
	connSet := &testConnSet{
		t:      t,
		closed: make(map[net.Conn]bool),
	}
	dial := func(n, addr string) (net.Conn, error) {
		c, err := net.Dial(n, addr)
		if err != nil {
			return nil, err
		}
		tc := &testCloseConn{c, connSet}
		connSet.insert(tc)
		return tc, nil
	}
	return connSet, dial
}

func (tcs *testConnSet) check(t *testing.T) {
	tcs.mutex.Lock()
	defer tcs.mutex.Unlock()

	for i, c := range tcs.list {
		if !tcs.closed[c] {
			t.Errorf("TCP connection #%d, %p (of %d total) was not closed", i+1, c, len(tcs.list))
		}
	}
}

// Two subsequent requests and verify their response is the same.
// The response from the server is our own IP:port
func TestTransportKeepAlives(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	for _, disableKeepAlive := range []bool{false, true} {
		tr := &Transport{DisableKeepAlives: disableKeepAlive}
		defer tr.CloseIdleConnections()
		c := &Client{Transport: tr}

		fetch := func(n int) string {
			res, err := c.Get(ts.URL)
			if err != nil {
				t.Fatalf("error in disableKeepAlive=%v, req #%d, GET: %v", disableKeepAlive, n, err)
			}
			body, err := ioutil.ReadAll(res.Body)
			if err != nil {
				t.Fatalf("error in disableKeepAlive=%v, req #%d, ReadAll: %v", disableKeepAlive, n, err)
			}
			return string(body)
		}

		body1 := fetch(1)
		body2 := fetch(2)

		bodiesDiffer := body1 != body2
		if bodiesDiffer != disableKeepAlive {
			t.Errorf("error in disableKeepAlive=%v. unexpected bodiesDiffer=%v; body1=%q; body2=%q",
				disableKeepAlive, bodiesDiffer, body1, body2)
		}
	}
}

func TestTransportConnectionCloseOnResponse(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	connSet, testDial := makeTestDial(t)

	for _, connectionClose := range []bool{false, true} {
		tr := &Transport{
			Dial: testDial,
		}
		c := &Client{Transport: tr}

		fetch := func(n int) string {
			req := new(Request)
			var err error
			req.URL, err = url.Parse(ts.URL + fmt.Sprintf("/?close=%v", connectionClose))
			if err != nil {
				t.Fatalf("URL parse error: %v", err)
			}
			req.Method = "GET"
			req.Proto = "HTTP/1.1"
			req.ProtoMajor = 1
			req.ProtoMinor = 1

			res, err := c.Do(req)
			if err != nil {
				t.Fatalf("error in connectionClose=%v, req #%d, Do: %v", connectionClose, n, err)
			}
			defer res.Body.Close()
			body, err := ioutil.ReadAll(res.Body)
			if err != nil {
				t.Fatalf("error in connectionClose=%v, req #%d, ReadAll: %v", connectionClose, n, err)
			}
			return string(body)
		}

		body1 := fetch(1)
		body2 := fetch(2)
		bodiesDiffer := body1 != body2
		if bodiesDiffer != connectionClose {
			t.Errorf("error in connectionClose=%v. unexpected bodiesDiffer=%v; body1=%q; body2=%q",
				connectionClose, bodiesDiffer, body1, body2)
		}

		tr.CloseIdleConnections()
	}

	connSet.check(t)
}

func TestTransportConnectionCloseOnRequest(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	connSet, testDial := makeTestDial(t)

	for _, connectionClose := range []bool{false, true} {
		tr := &Transport{
			Dial: testDial,
		}
		c := &Client{Transport: tr}

		fetch := func(n int) string {
			req := new(Request)
			var err error
			req.URL, err = url.Parse(ts.URL)
			if err != nil {
				t.Fatalf("URL parse error: %v", err)
			}
			req.Method = "GET"
			req.Proto = "HTTP/1.1"
			req.ProtoMajor = 1
			req.ProtoMinor = 1
			req.Close = connectionClose

			res, err := c.Do(req)
			if err != nil {
				t.Fatalf("error in connectionClose=%v, req #%d, Do: %v", connectionClose, n, err)
			}
			body, err := ioutil.ReadAll(res.Body)
			if err != nil {
				t.Fatalf("error in connectionClose=%v, req #%d, ReadAll: %v", connectionClose, n, err)
			}
			return string(body)
		}

		body1 := fetch(1)
		body2 := fetch(2)
		bodiesDiffer := body1 != body2
		if bodiesDiffer != connectionClose {
			t.Errorf("error in connectionClose=%v. unexpected bodiesDiffer=%v; body1=%q; body2=%q",
				connectionClose, bodiesDiffer, body1, body2)
		}

		tr.CloseIdleConnections()
	}

	connSet.check(t)
}

func TestTransportIdleCacheKeys(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	tr := &Transport{DisableKeepAlives: false}
	c := &Client{Transport: tr}

	if e, g := 0, len(tr.IdleConnKeysForTesting()); e != g {
		t.Errorf("After CloseIdleConnections expected %d idle conn cache keys; got %d", e, g)
	}

	resp, err := c.Get(ts.URL)
	if err != nil {
		t.Error(err)
	}
	ioutil.ReadAll(resp.Body)

	keys := tr.IdleConnKeysForTesting()
	if e, g := 1, len(keys); e != g {
		t.Fatalf("After Get expected %d idle conn cache keys; got %d", e, g)
	}

	if e := "|http|" + ts.Listener.Addr().String(); keys[0] != e {
		t.Errorf("Expected idle cache key %q; got %q", e, keys[0])
	}

	tr.CloseIdleConnections()
	if e, g := 0, len(tr.IdleConnKeysForTesting()); e != g {
		t.Errorf("After CloseIdleConnections expected %d idle conn cache keys; got %d", e, g)
	}
}

func TestTransportMaxPerHostIdleConns(t *testing.T) {
	defer afterTest(t)
	resch := make(chan string)
	gotReq := make(chan bool)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		gotReq <- true
		msg := <-resch
		_, err := w.Write([]byte(msg))
		if err != nil {
			t.Fatalf("Write: %v", err)
		}
	}))
	defer ts.Close()
	maxIdleConns := 2
	tr := &Transport{DisableKeepAlives: false, MaxIdleConnsPerHost: maxIdleConns}
	c := &Client{Transport: tr}

	// Start 3 outstanding requests and wait for the server to get them.
	// Their responses will hang until we write to resch, though.
	donech := make(chan bool)
	doReq := func() {
		resp, err := c.Get(ts.URL)
		if err != nil {
			t.Error(err)
		}
		_, err = ioutil.ReadAll(resp.Body)
		if err != nil {
			t.Fatalf("ReadAll: %v", err)
		}
		donech <- true
	}
	go doReq()
	<-gotReq
	go doReq()
	<-gotReq
	go doReq()
	<-gotReq

	if e, g := 0, len(tr.IdleConnKeysForTesting()); e != g {
		t.Fatalf("Before writes, expected %d idle conn cache keys; got %d", e, g)
	}

	resch <- "res1"
	<-donech
	keys := tr.IdleConnKeysForTesting()
	if e, g := 1, len(keys); e != g {
		t.Fatalf("after first response, expected %d idle conn cache keys; got %d", e, g)
	}
	cacheKey := "|http|" + ts.Listener.Addr().String()
	if keys[0] != cacheKey {
		t.Fatalf("Expected idle cache key %q; got %q", cacheKey, keys[0])
	}
	if e, g := 1, tr.IdleConnCountForTesting(cacheKey); e != g {
		t.Errorf("after first response, expected %d idle conns; got %d", e, g)
	}

	resch <- "res2"
	<-donech
	if e, g := 2, tr.IdleConnCountForTesting(cacheKey); e != g {
		t.Errorf("after second response, expected %d idle conns; got %d", e, g)
	}

	resch <- "res3"
	<-donech
	if e, g := maxIdleConns, tr.IdleConnCountForTesting(cacheKey); e != g {
		t.Errorf("after third response, still expected %d idle conns; got %d", e, g)
	}
}

func TestTransportServerClosingUnexpectedly(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	tr := &Transport{}
	c := &Client{Transport: tr}

	fetch := func(n, retries int) string {
		condFatalf := func(format string, arg ...interface{}) {
			if retries <= 0 {
				t.Fatalf(format, arg...)
			}
			t.Logf("retrying shortly after expected error: "+format, arg...)
			time.Sleep(time.Second / time.Duration(retries))
		}
		for retries >= 0 {
			retries--
			res, err := c.Get(ts.URL)
			if err != nil {
				condFatalf("error in req #%d, GET: %v", n, err)
				continue
			}
			body, err := ioutil.ReadAll(res.Body)
			if err != nil {
				condFatalf("error in req #%d, ReadAll: %v", n, err)
				continue
			}
			res.Body.Close()
			return string(body)
		}
		panic("unreachable")
	}

	body1 := fetch(1, 0)
	body2 := fetch(2, 0)

	ts.CloseClientConnections() // surprise!

	// This test has an expected race. Sleeping for 25 ms prevents
	// it on most fast machines, causing the next fetch() call to
	// succeed quickly.  But if we do get errors, fetch() will retry 5
	// times with some delays between.
	time.Sleep(25 * time.Millisecond)

	body3 := fetch(3, 5)

	if body1 != body2 {
		t.Errorf("expected body1 and body2 to be equal")
	}
	if body2 == body3 {
		t.Errorf("expected body2 and body3 to be different")
	}
}

// Test for http://golang.org/issue/2616 (appropriate issue number)
// This fails pretty reliably with GOMAXPROCS=100 or something high.
func TestStressSurpriseServerCloses(t *testing.T) {
	defer afterTest(t)
	if testing.Short() {
		t.Skip("skipping test in short mode")
	}
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		w.Header().Set("Content-Length", "5")
		w.Header().Set("Content-Type", "text/plain")
		w.Write([]byte("Hello"))
		w.(Flusher).Flush()
		conn, buf, _ := w.(Hijacker).Hijack()
		buf.Flush()
		conn.Close()
	}))
	defer ts.Close()

	tr := &Transport{DisableKeepAlives: false}
	c := &Client{Transport: tr}

	// Do a bunch of traffic from different goroutines. Send to activityc
	// after each request completes, regardless of whether it failed.
	const (
		numClients    = 50
		reqsPerClient = 250
	)
	activityc := make(chan bool)
	for i := 0; i < numClients; i++ {
		go func() {
			for i := 0; i < reqsPerClient; i++ {
				res, err := c.Get(ts.URL)
				if err == nil {
					// We expect errors since the server is
					// hanging up on us after telling us to
					// send more requests, so we don't
					// actually care what the error is.
					// But we want to close the body in cases
					// where we won the race.
					res.Body.Close()
				}
				activityc <- true
			}
		}()
	}

	// Make sure all the request come back, one way or another.
	for i := 0; i < numClients*reqsPerClient; i++ {
		select {
		case <-activityc:
		case <-time.After(5 * time.Second):
			t.Fatalf("presumed deadlock; no HTTP client activity seen in awhile")
		}
	}
}

// TestTransportHeadResponses verifies that we deal with Content-Lengths
// with no bodies properly
func TestTransportHeadResponses(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		if r.Method != "HEAD" {
			panic("expected HEAD; got " + r.Method)
		}
		w.Header().Set("Content-Length", "123")
		w.WriteHeader(200)
	}))
	defer ts.Close()

	tr := &Transport{DisableKeepAlives: false}
	c := &Client{Transport: tr}
	for i := 0; i < 2; i++ {
		res, err := c.Head(ts.URL)
		if err != nil {
			t.Errorf("error on loop %d: %v", i, err)
			continue
		}
		if e, g := "123", res.Header.Get("Content-Length"); e != g {
			t.Errorf("loop %d: expected Content-Length header of %q, got %q", i, e, g)
		}
		if e, g := int64(123), res.ContentLength; e != g {
			t.Errorf("loop %d: expected res.ContentLength of %v, got %v", i, e, g)
		}
		if all, err := ioutil.ReadAll(res.Body); err != nil {
			t.Errorf("loop %d: Body ReadAll: %v", i, err)
		} else if len(all) != 0 {
			t.Errorf("Bogus body %q", all)
		}
	}
}

// TestTransportHeadChunkedResponse verifies that we ignore chunked transfer-encoding
// on responses to HEAD requests.
func TestTransportHeadChunkedResponse(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		if r.Method != "HEAD" {
			panic("expected HEAD; got " + r.Method)
		}
		w.Header().Set("Transfer-Encoding", "chunked") // client should ignore
		w.Header().Set("x-client-ipport", r.RemoteAddr)
		w.WriteHeader(200)
	}))
	defer ts.Close()

	tr := &Transport{DisableKeepAlives: false}
	c := &Client{Transport: tr}

	res1, err := c.Head(ts.URL)
	if err != nil {
		t.Fatalf("request 1 error: %v", err)
	}
	res2, err := c.Head(ts.URL)
	if err != nil {
		t.Fatalf("request 2 error: %v", err)
	}
	if v1, v2 := res1.Header.Get("x-client-ipport"), res2.Header.Get("x-client-ipport"); v1 != v2 {
		t.Errorf("ip/ports differed between head requests: %q vs %q", v1, v2)
	}
}

var roundTripTests = []struct {
	accept       string
	expectAccept string
	compressed   bool
}{
	// Requests with no accept-encoding header use transparent compression
	{"", "gzip", false},
	// Requests with other accept-encoding should pass through unmodified
	{"foo", "foo", false},
	// Requests with accept-encoding == gzip should be passed through
	{"gzip", "gzip", true},
}

// Test that the modification made to the Request by the RoundTripper is cleaned up
func TestRoundTripGzip(t *testing.T) {
	defer afterTest(t)
	const responseBody = "test response body"
	ts := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, req *Request) {
		accept := req.Header.Get("Accept-Encoding")
		if expect := req.FormValue("expect_accept"); accept != expect {
			t.Errorf("in handler, test %v: Accept-Encoding = %q, want %q",
				req.FormValue("testnum"), accept, expect)
		}
		if accept == "gzip" {
			rw.Header().Set("Content-Encoding", "gzip")
			gz := gzip.NewWriter(rw)
			gz.Write([]byte(responseBody))
			gz.Close()
		} else {
			rw.Header().Set("Content-Encoding", accept)
			rw.Write([]byte(responseBody))
		}
	}))
	defer ts.Close()

	for i, test := range roundTripTests {
		// Test basic request (no accept-encoding)
		req, _ := NewRequest("GET", fmt.Sprintf("%s/?testnum=%d&expect_accept=%s", ts.URL, i, test.expectAccept), nil)
		if test.accept != "" {
			req.Header.Set("Accept-Encoding", test.accept)
		}
		res, err := DefaultTransport.RoundTrip(req)
		var body []byte
		if test.compressed {
			var r *gzip.Reader
			r, err = gzip.NewReader(res.Body)
			if err != nil {
				t.Errorf("%d. gzip NewReader: %v", i, err)
				continue
			}
			body, err = ioutil.ReadAll(r)
			res.Body.Close()
		} else {
			body, err = ioutil.ReadAll(res.Body)
		}
		if err != nil {
			t.Errorf("%d. Error: %q", i, err)
			continue
		}
		if g, e := string(body), responseBody; g != e {
			t.Errorf("%d. body = %q; want %q", i, g, e)
		}
		if g, e := req.Header.Get("Accept-Encoding"), test.accept; g != e {
			t.Errorf("%d. Accept-Encoding = %q; want %q (it was mutated, in violation of RoundTrip contract)", i, g, e)
		}
		if g, e := res.Header.Get("Content-Encoding"), test.accept; g != e {
			t.Errorf("%d. Content-Encoding = %q; want %q", i, g, e)
		}
	}

}

func TestTransportGzip(t *testing.T) {
	defer afterTest(t)
	const testString = "The test string aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
	const nRandBytes = 1024 * 1024
	ts := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, req *Request) {
		if req.Method == "HEAD" {
			if g := req.Header.Get("Accept-Encoding"); g != "" {
				t.Errorf("HEAD request sent with Accept-Encoding of %q; want none", g)
			}
			return
		}
		if g, e := req.Header.Get("Accept-Encoding"), "gzip"; g != e {
			t.Errorf("Accept-Encoding = %q, want %q", g, e)
		}
		rw.Header().Set("Content-Encoding", "gzip")

		var w io.Writer = rw
		var buf bytes.Buffer
		if req.FormValue("chunked") == "0" {
			w = &buf
			defer io.Copy(rw, &buf)
			defer func() {
				rw.Header().Set("Content-Length", strconv.Itoa(buf.Len()))
			}()
		}
		gz := gzip.NewWriter(w)
		gz.Write([]byte(testString))
		if req.FormValue("body") == "large" {
			io.CopyN(gz, rand.Reader, nRandBytes)
		}
		gz.Close()
	}))
	defer ts.Close()

	for _, chunked := range []string{"1", "0"} {
		c := &Client{Transport: &Transport{}}

		// First fetch something large, but only read some of it.
		res, err := c.Get(ts.URL + "/?body=large&chunked=" + chunked)
		if err != nil {
			t.Fatalf("large get: %v", err)
		}
		buf := make([]byte, len(testString))
		n, err := io.ReadFull(res.Body, buf)
		if err != nil {
			t.Fatalf("partial read of large response: size=%d, %v", n, err)
		}
		if e, g := testString, string(buf); e != g {
			t.Errorf("partial read got %q, expected %q", g, e)
		}
		res.Body.Close()
		// Read on the body, even though it's closed
		n, err = res.Body.Read(buf)
		if n != 0 || err == nil {
			t.Errorf("expected error post-closed large Read; got = %d, %v", n, err)
		}

		// Then something small.
		res, err = c.Get(ts.URL + "/?chunked=" + chunked)
		if err != nil {
			t.Fatal(err)
		}
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			t.Fatal(err)
		}
		if g, e := string(body), testString; g != e {
			t.Fatalf("body = %q; want %q", g, e)
		}
		if g, e := res.Header.Get("Content-Encoding"), ""; g != e {
			t.Fatalf("Content-Encoding = %q; want %q", g, e)
		}

		// Read on the body after it's been fully read:
		n, err = res.Body.Read(buf)
		if n != 0 || err == nil {
			t.Errorf("expected Read error after exhausted reads; got %d, %v", n, err)
		}
		res.Body.Close()
		n, err = res.Body.Read(buf)
		if n != 0 || err == nil {
			t.Errorf("expected Read error after Close; got %d, %v", n, err)
		}
	}

	// And a HEAD request too, because they're always weird.
	c := &Client{Transport: &Transport{}}
	res, err := c.Head(ts.URL)
	if err != nil {
		t.Fatalf("Head: %v", err)
	}
	if res.StatusCode != 200 {
		t.Errorf("Head status=%d; want=200", res.StatusCode)
	}
}

func TestTransportProxy(t *testing.T) {
	defer afterTest(t)
	ch := make(chan string, 1)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		ch <- "real server"
	}))
	defer ts.Close()
	proxy := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		ch <- "proxy for " + r.URL.String()
	}))
	defer proxy.Close()

	pu, err := url.Parse(proxy.URL)
	if err != nil {
		t.Fatal(err)
	}
	c := &Client{Transport: &Transport{Proxy: ProxyURL(pu)}}
	c.Head(ts.URL)
	got := <-ch
	want := "proxy for " + ts.URL + "/"
	if got != want {
		t.Errorf("want %q, got %q", want, got)
	}
}

// TestTransportGzipRecursive sends a gzip quine and checks that the
// client gets the same value back. This is more cute than anything,
// but checks that we don't recurse forever, and checks that
// Content-Encoding is removed.
func TestTransportGzipRecursive(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		w.Header().Set("Content-Encoding", "gzip")
		w.Write(rgz)
	}))
	defer ts.Close()

	c := &Client{Transport: &Transport{}}
	res, err := c.Get(ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(body, rgz) {
		t.Fatalf("Incorrect result from recursive gz:\nhave=%x\nwant=%x",
			body, rgz)
	}
	if g, e := res.Header.Get("Content-Encoding"), ""; g != e {
		t.Fatalf("Content-Encoding = %q; want %q", g, e)
	}
}

// tests that persistent goroutine connections shut down when no longer desired.
func TestTransportPersistConnLeak(t *testing.T) {
	defer afterTest(t)
	gotReqCh := make(chan bool)
	unblockCh := make(chan bool)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		gotReqCh <- true
		<-unblockCh
		w.Header().Set("Content-Length", "0")
		w.WriteHeader(204)
	}))
	defer ts.Close()

	tr := &Transport{}
	c := &Client{Transport: tr}

	n0 := runtime.NumGoroutine()

	const numReq = 25
	didReqCh := make(chan bool)
	for i := 0; i < numReq; i++ {
		go func() {
			res, err := c.Get(ts.URL)
			didReqCh <- true
			if err != nil {
				t.Errorf("client fetch error: %v", err)
				return
			}
			res.Body.Close()
		}()
	}

	// Wait for all goroutines to be stuck in the Handler.
	for i := 0; i < numReq; i++ {
		<-gotReqCh
	}

	nhigh := runtime.NumGoroutine()

	// Tell all handlers to unblock and reply.
	for i := 0; i < numReq; i++ {
		unblockCh <- true
	}

	// Wait for all HTTP clients to be done.
	for i := 0; i < numReq; i++ {
		<-didReqCh
	}

	tr.CloseIdleConnections()
	time.Sleep(100 * time.Millisecond)
	runtime.GC()
	runtime.GC() // even more.
	nfinal := runtime.NumGoroutine()

	growth := nfinal - n0

	// We expect 0 or 1 extra goroutine, empirically.  Allow up to 5.
	// Previously we were leaking one per numReq.
	t.Logf("goroutine growth: %d -> %d -> %d (delta: %d)", n0, nhigh, nfinal, growth)
	if int(growth) > 5 {
		t.Error("too many new goroutines")
	}
}

// golang.org/issue/4531: Transport leaks goroutines when
// request.ContentLength is explicitly short
func TestTransportPersistConnLeakShortBody(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
	}))
	defer ts.Close()

	tr := &Transport{}
	c := &Client{Transport: tr}

	n0 := runtime.NumGoroutine()
	body := []byte("Hello")
	for i := 0; i < 20; i++ {
		req, err := NewRequest("POST", ts.URL, bytes.NewReader(body))
		if err != nil {
			t.Fatal(err)
		}
		req.ContentLength = int64(len(body) - 2) // explicitly short
		_, err = c.Do(req)
		if err == nil {
			t.Fatal("Expect an error from writing too long of a body.")
		}
	}
	nhigh := runtime.NumGoroutine()
	tr.CloseIdleConnections()
	time.Sleep(400 * time.Millisecond)
	runtime.GC()
	nfinal := runtime.NumGoroutine()

	growth := nfinal - n0

	// We expect 0 or 1 extra goroutine, empirically.  Allow up to 5.
	// Previously we were leaking one per numReq.
	t.Logf("goroutine growth: %d -> %d -> %d (delta: %d)", n0, nhigh, nfinal, growth)
	if int(growth) > 5 {
		t.Error("too many new goroutines")
	}
}

// This used to crash; http://golang.org/issue/3266
func TestTransportIdleConnCrash(t *testing.T) {
	defer afterTest(t)
	tr := &Transport{}
	c := &Client{Transport: tr}

	unblockCh := make(chan bool, 1)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		<-unblockCh
		tr.CloseIdleConnections()
	}))
	defer ts.Close()

	didreq := make(chan bool)
	go func() {
		res, err := c.Get(ts.URL)
		if err != nil {
			t.Error(err)
		} else {
			res.Body.Close() // returns idle conn
		}
		didreq <- true
	}()
	unblockCh <- true
	<-didreq
}

// Test that the transport doesn't close the TCP connection early,
// before the response body has been read.  This was a regression
// which sadly lacked a triggering test.  The large response body made
// the old race easier to trigger.
func TestIssue3644(t *testing.T) {
	defer afterTest(t)
	const numFoos = 5000
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		w.Header().Set("Connection", "close")
		for i := 0; i < numFoos; i++ {
			w.Write([]byte("foo "))
		}
	}))
	defer ts.Close()
	tr := &Transport{}
	c := &Client{Transport: tr}
	res, err := c.Get(ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	defer res.Body.Close()
	bs, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Fatal(err)
	}
	if len(bs) != numFoos*len("foo ") {
		t.Errorf("unexpected response length")
	}
}

// Test that a client receives a server's reply, even if the server doesn't read
// the entire request body.
func TestIssue3595(t *testing.T) {
	defer afterTest(t)
	const deniedMsg = "sorry, denied."
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		Error(w, deniedMsg, StatusUnauthorized)
	}))
	defer ts.Close()
	tr := &Transport{}
	c := &Client{Transport: tr}
	res, err := c.Post(ts.URL, "application/octet-stream", neverEnding('a'))
	if err != nil {
		t.Errorf("Post: %v", err)
		return
	}
	got, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Fatalf("Body ReadAll: %v", err)
	}
	if !strings.Contains(string(got), deniedMsg) {
		t.Errorf("Known bug: response %q does not contain %q", got, deniedMsg)
	}
}

// From http://golang.org/issue/4454 ,
// "client fails to handle requests with no body and chunked encoding"
func TestChunkedNoContent(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		w.WriteHeader(StatusNoContent)
	}))
	defer ts.Close()

	for _, closeBody := range []bool{true, false} {
		c := &Client{Transport: &Transport{}}
		const n = 4
		for i := 1; i <= n; i++ {
			res, err := c.Get(ts.URL)
			if err != nil {
				t.Errorf("closingBody=%v, req %d/%d: %v", closeBody, i, n, err)
			} else {
				if closeBody {
					res.Body.Close()
				}
			}
		}
	}
}

func TestTransportConcurrency(t *testing.T) {
	defer afterTest(t)
	maxProcs, numReqs := 16, 500
	if testing.Short() {
		maxProcs, numReqs = 4, 50
	}
	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(maxProcs))
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		fmt.Fprintf(w, "%v", r.FormValue("echo"))
	}))
	defer ts.Close()

	var wg sync.WaitGroup
	wg.Add(numReqs)

	tr := &Transport{
		Dial: func(netw, addr string) (c net.Conn, err error) {
			// Due to the Transport's "socket late
			// binding" (see idleConnCh in transport.go),
			// the numReqs HTTP requests below can finish
			// with a dial still outstanding.  So count
			// our dials as work too so the leak checker
			// doesn't complain at us.
			wg.Add(1)
			defer wg.Done()
			return net.Dial(netw, addr)
		},
	}
	defer tr.CloseIdleConnections()
	c := &Client{Transport: tr}
	reqs := make(chan string)
	defer close(reqs)

	for i := 0; i < maxProcs*2; i++ {
		go func() {
			for req := range reqs {
				res, err := c.Get(ts.URL + "/?echo=" + req)
				if err != nil {
					t.Errorf("error on req %s: %v", req, err)
					wg.Done()
					continue
				}
				all, err := ioutil.ReadAll(res.Body)
				if err != nil {
					t.Errorf("read error on req %s: %v", req, err)
					wg.Done()
					continue
				}
				if string(all) != req {
					t.Errorf("body of req %s = %q; want %q", req, all, req)
				}
				res.Body.Close()
				wg.Done()
			}
		}()
	}
	for i := 0; i < numReqs; i++ {
		reqs <- fmt.Sprintf("request-%d", i)
	}
	wg.Wait()
}

func TestIssue4191_InfiniteGetTimeout(t *testing.T) {
	defer afterTest(t)
	const debug = false
	mux := NewServeMux()
	mux.HandleFunc("/get", func(w ResponseWriter, r *Request) {
		io.Copy(w, neverEnding('a'))
	})
	ts := httptest.NewServer(mux)
	timeout := 100 * time.Millisecond

	client := &Client{
		Transport: &Transport{
			Dial: func(n, addr string) (net.Conn, error) {
				conn, err := net.Dial(n, addr)
				if err != nil {
					return nil, err
				}
				conn.SetDeadline(time.Now().Add(timeout))
				if debug {
					conn = NewLoggingConn("client", conn)
				}
				return conn, nil
			},
			DisableKeepAlives: true,
		},
	}

	getFailed := false
	nRuns := 5
	if testing.Short() {
		nRuns = 1
	}
	for i := 0; i < nRuns; i++ {
		if debug {
			println("run", i+1, "of", nRuns)
		}
		sres, err := client.Get(ts.URL + "/get")
		if err != nil {
			if !getFailed {
				// Make the timeout longer, once.
				getFailed = true
				t.Logf("increasing timeout")
				i--
				timeout *= 10
				continue
			}
			t.Errorf("Error issuing GET: %v", err)
			break
		}
		_, err = io.Copy(ioutil.Discard, sres.Body)
		if err == nil {
			t.Errorf("Unexpected successful copy")
			break
		}
	}
	if debug {
		println("tests complete; waiting for handlers to finish")
	}
	ts.Close()
}

func TestIssue4191_InfiniteGetToPutTimeout(t *testing.T) {
	defer afterTest(t)
	const debug = false
	mux := NewServeMux()
	mux.HandleFunc("/get", func(w ResponseWriter, r *Request) {
		io.Copy(w, neverEnding('a'))
	})
	mux.HandleFunc("/put", func(w ResponseWriter, r *Request) {
		defer r.Body.Close()
		io.Copy(ioutil.Discard, r.Body)
	})
	ts := httptest.NewServer(mux)
	timeout := 100 * time.Millisecond

	client := &Client{
		Transport: &Transport{
			Dial: func(n, addr string) (net.Conn, error) {
				conn, err := net.Dial(n, addr)
				if err != nil {
					return nil, err
				}
				conn.SetDeadline(time.Now().Add(timeout))
				if debug {
					conn = NewLoggingConn("client", conn)
				}
				return conn, nil
			},
			DisableKeepAlives: true,
		},
	}

	getFailed := false
	nRuns := 5
	if testing.Short() {
		nRuns = 1
	}
	for i := 0; i < nRuns; i++ {
		if debug {
			println("run", i+1, "of", nRuns)
		}
		sres, err := client.Get(ts.URL + "/get")
		if err != nil {
			if !getFailed {
				// Make the timeout longer, once.
				getFailed = true
				t.Logf("increasing timeout")
				i--
				timeout *= 10
				continue
			}
			t.Errorf("Error issuing GET: %v", err)
			break
		}
		req, _ := NewRequest("PUT", ts.URL+"/put", sres.Body)
		_, err = client.Do(req)
		if err == nil {
			sres.Body.Close()
			t.Errorf("Unexpected successful PUT")
			break
		}
		sres.Body.Close()
	}
	if debug {
		println("tests complete; waiting for handlers to finish")
	}
	ts.Close()
}

func TestTransportResponseHeaderTimeout(t *testing.T) {
	defer afterTest(t)
	if testing.Short() {
		t.Skip("skipping timeout test in -short mode")
	}
	mux := NewServeMux()
	mux.HandleFunc("/fast", func(w ResponseWriter, r *Request) {})
	mux.HandleFunc("/slow", func(w ResponseWriter, r *Request) {
		time.Sleep(2 * time.Second)
	})
	ts := httptest.NewServer(mux)
	defer ts.Close()

	tr := &Transport{
		ResponseHeaderTimeout: 500 * time.Millisecond,
	}
	defer tr.CloseIdleConnections()
	c := &Client{Transport: tr}

	tests := []struct {
		path    string
		want    int
		wantErr string
	}{
		{path: "/fast", want: 200},
		{path: "/slow", wantErr: "timeout awaiting response headers"},
		{path: "/fast", want: 200},
	}
	for i, tt := range tests {
		res, err := c.Get(ts.URL + tt.path)
		if err != nil {
			if strings.Contains(err.Error(), tt.wantErr) {
				continue
			}
			t.Errorf("%d. unexpected error: %v", i, err)
			continue
		}
		if tt.wantErr != "" {
			t.Errorf("%d. no error. expected error: %v", i, tt.wantErr)
			continue
		}
		if res.StatusCode != tt.want {
			t.Errorf("%d for path %q status = %d; want %d", i, tt.path, res.StatusCode, tt.want)
		}
	}
}

func TestTransportCancelRequest(t *testing.T) {
	defer afterTest(t)
	if testing.Short() {
		t.Skip("skipping test in -short mode")
	}
	unblockc := make(chan bool)
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		fmt.Fprintf(w, "Hello")
		w.(Flusher).Flush() // send headers and some body
		<-unblockc
	}))
	defer ts.Close()
	defer close(unblockc)

	tr := &Transport{}
	defer tr.CloseIdleConnections()
	c := &Client{Transport: tr}

	req, _ := NewRequest("GET", ts.URL, nil)
	res, err := c.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	go func() {
		time.Sleep(1 * time.Second)
		tr.CancelRequest(req)
	}()
	t0 := time.Now()
	body, err := ioutil.ReadAll(res.Body)
	d := time.Since(t0)

	if err == nil {
		t.Error("expected an error reading the body")
	}
	if string(body) != "Hello" {
		t.Errorf("Body = %q; want Hello", body)
	}
	if d < 500*time.Millisecond {
		t.Errorf("expected ~1 second delay; got %v", d)
	}
	// Verify no outstanding requests after readLoop/writeLoop
	// goroutines shut down.
	for tries := 3; tries > 0; tries-- {
		n := tr.NumPendingRequestsForTesting()
		if n == 0 {
			break
		}
		time.Sleep(100 * time.Millisecond)
		if tries == 1 {
			t.Errorf("pending requests = %d; want 0", n)
		}
	}
}

// golang.org/issue/3672 -- Client can't close HTTP stream
// Calling Close on a Response.Body used to just read until EOF.
// Now it actually closes the TCP connection.
func TestTransportCloseResponseBody(t *testing.T) {
	defer afterTest(t)
	writeErr := make(chan error, 1)
	msg := []byte("young\n")
	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		for {
			_, err := w.Write(msg)
			if err != nil {
				writeErr <- err
				return
			}
			w.(Flusher).Flush()
		}
	}))
	defer ts.Close()

	tr := &Transport{}
	defer tr.CloseIdleConnections()
	c := &Client{Transport: tr}

	req, _ := NewRequest("GET", ts.URL, nil)
	defer tr.CancelRequest(req)

	res, err := c.Do(req)
	if err != nil {
		t.Fatal(err)
	}

	const repeats = 3
	buf := make([]byte, len(msg)*repeats)
	want := bytes.Repeat(msg, repeats)

	_, err = io.ReadFull(res.Body, buf)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(buf, want) {
		t.Errorf("read %q; want %q", buf, want)
	}
	didClose := make(chan error, 1)
	go func() {
		didClose <- res.Body.Close()
	}()
	select {
	case err := <-didClose:
		if err != nil {
			t.Errorf("Close = %v", err)
		}
	case <-time.After(10 * time.Second):
		t.Fatal("too long waiting for close")
	}
	select {
	case err := <-writeErr:
		if err == nil {
			t.Errorf("expected non-nil write error")
		}
	case <-time.After(10 * time.Second):
		t.Fatal("too long waiting for write error")
	}
}

type fooProto struct{}

func (fooProto) RoundTrip(req *Request) (*Response, error) {
	res := &Response{
		Status:     "200 OK",
		StatusCode: 200,
		Header:     make(Header),
		Body:       ioutil.NopCloser(strings.NewReader("You wanted " + req.URL.String())),
	}
	return res, nil
}

func TestTransportAltProto(t *testing.T) {
	defer afterTest(t)
	tr := &Transport{}
	c := &Client{Transport: tr}
	tr.RegisterProtocol("foo", fooProto{})
	res, err := c.Get("foo://bar.com/path")
	if err != nil {
		t.Fatal(err)
	}
	bodyb, err := ioutil.ReadAll(res.Body)
	if err != nil {
		t.Fatal(err)
	}
	body := string(bodyb)
	if e := "You wanted foo://bar.com/path"; body != e {
		t.Errorf("got response %q, want %q", body, e)
	}
}

func TestTransportNoHost(t *testing.T) {
	defer afterTest(t)
	tr := &Transport{}
	_, err := tr.RoundTrip(&Request{
		Header: make(Header),
		URL: &url.URL{
			Scheme: "http",
		},
	})
	want := "http: no Host in request URL"
	if got := fmt.Sprint(err); got != want {
		t.Errorf("error = %v; want %q", err, want)
	}
}

func TestTransportSocketLateBinding(t *testing.T) {
	defer afterTest(t)

	mux := NewServeMux()
	fooGate := make(chan bool, 1)
	mux.HandleFunc("/foo", func(w ResponseWriter, r *Request) {
		w.Header().Set("foo-ipport", r.RemoteAddr)
		w.(Flusher).Flush()
		<-fooGate
	})
	mux.HandleFunc("/bar", func(w ResponseWriter, r *Request) {
		w.Header().Set("bar-ipport", r.RemoteAddr)
	})
	ts := httptest.NewServer(mux)
	defer ts.Close()

	dialGate := make(chan bool, 1)
	tr := &Transport{
		Dial: func(n, addr string) (net.Conn, error) {
			<-dialGate
			return net.Dial(n, addr)
		},
		DisableKeepAlives: false,
	}
	defer tr.CloseIdleConnections()
	c := &Client{
		Transport: tr,
	}

	dialGate <- true // only allow one dial
	fooRes, err := c.Get(ts.URL + "/foo")
	if err != nil {
		t.Fatal(err)
	}
	fooAddr := fooRes.Header.Get("foo-ipport")
	if fooAddr == "" {
		t.Fatal("No addr on /foo request")
	}
	time.AfterFunc(200*time.Millisecond, func() {
		// let the foo response finish so we can use its
		// connection for /bar
		fooGate <- true
		io.Copy(ioutil.Discard, fooRes.Body)
		fooRes.Body.Close()
	})

	barRes, err := c.Get(ts.URL + "/bar")
	if err != nil {
		t.Fatal(err)
	}
	barAddr := barRes.Header.Get("bar-ipport")
	if barAddr != fooAddr {
		t.Fatalf("/foo came from conn %q; /bar came from %q instead", fooAddr, barAddr)
	}
	barRes.Body.Close()
	dialGate <- true
}

// Issue 2184
func TestTransportReading100Continue(t *testing.T) {
	defer afterTest(t)

	const numReqs = 5
	reqBody := func(n int) string { return fmt.Sprintf("request body %d", n) }
	reqID := func(n int) string { return fmt.Sprintf("REQ-ID-%d", n) }

	send100Response := func(w *io.PipeWriter, r *io.PipeReader) {
		defer w.Close()
		defer r.Close()
		br := bufio.NewReader(r)
		n := 0
		for {
			n++
			req, err := ReadRequest(br)
			if err == io.EOF {
				return
			}
			if err != nil {
				t.Error(err)
				return
			}
			slurp, err := ioutil.ReadAll(req.Body)
			if err != nil {
				t.Errorf("Server request body slurp: %v", err)
				return
			}
			id := req.Header.Get("Request-Id")
			resCode := req.Header.Get("X-Want-Response-Code")
			if resCode == "" {
				resCode = "100 Continue"
				if string(slurp) != reqBody(n) {
					t.Errorf("Server got %q, %v; want %q", slurp, err, reqBody(n))
				}
			}
			body := fmt.Sprintf("Response number %d", n)
			v := []byte(strings.Replace(fmt.Sprintf(`HTTP/1.1 %s
Date: Thu, 28 Feb 2013 17:55:41 GMT

HTTP/1.1 200 OK
Content-Type: text/html
Echo-Request-Id: %s
Content-Length: %d

%s`, resCode, id, len(body), body), "\n", "\r\n", -1))
			w.Write(v)
			if id == reqID(numReqs) {
				return
			}
		}

	}

	tr := &Transport{
		Dial: func(n, addr string) (net.Conn, error) {
			sr, sw := io.Pipe() // server read/write
			cr, cw := io.Pipe() // client read/write
			conn := &rwTestConn{
				Reader: cr,
				Writer: sw,
				closeFunc: func() error {
					sw.Close()
					cw.Close()
					return nil
				},
			}
			go send100Response(cw, sr)
			return conn, nil
		},
		DisableKeepAlives: false,
	}
	defer tr.CloseIdleConnections()
	c := &Client{Transport: tr}

	testResponse := func(req *Request, name string, wantCode int) {
		res, err := c.Do(req)
		if err != nil {
			t.Fatalf("%s: Do: %v", name, err)
		}
		if res.StatusCode != wantCode {
			t.Fatalf("%s: Response Statuscode=%d; want %d", name, res.StatusCode, wantCode)
		}
		if id, idBack := req.Header.Get("Request-Id"), res.Header.Get("Echo-Request-Id"); id != "" && id != idBack {
			t.Errorf("%s: response id %q != request id %q", name, idBack, id)
		}
		_, err = ioutil.ReadAll(res.Body)
		if err != nil {
			t.Fatalf("%s: Slurp error: %v", name, err)
		}
	}

	// Few 100 responses, making sure we're not off-by-one.
	for i := 1; i <= numReqs; i++ {
		req, _ := NewRequest("POST", "http://dummy.tld/", strings.NewReader(reqBody(i)))
		req.Header.Set("Request-Id", reqID(i))
		testResponse(req, fmt.Sprintf("100, %d/%d", i, numReqs), 200)
	}

	// And some other informational 1xx but non-100 responses, to test
	// we return them but don't re-use the connection.
	for i := 1; i <= numReqs; i++ {
		req, _ := NewRequest("POST", "http://other.tld/", strings.NewReader(reqBody(i)))
		req.Header.Set("X-Want-Response-Code", "123 Sesame Street")
		testResponse(req, fmt.Sprintf("123, %d/%d", i, numReqs), 123)
	}
}

type proxyFromEnvTest struct {
	req     string // URL to fetch; blank means "http://example.com"
	env     string
	noenv   string
	want    string
	wanterr error
}

func (t proxyFromEnvTest) String() string {
	var buf bytes.Buffer
	if t.env != "" {
		fmt.Fprintf(&buf, "http_proxy=%q", t.env)
	}
	if t.noenv != "" {
		fmt.Fprintf(&buf, " no_proxy=%q", t.noenv)
	}
	req := "http://example.com"
	if t.req != "" {
		req = t.req
	}
	fmt.Fprintf(&buf, " req=%q", req)
	return strings.TrimSpace(buf.String())
}

var proxyFromEnvTests = []proxyFromEnvTest{
	{env: "127.0.0.1:8080", want: "http://127.0.0.1:8080"},
	{env: "cache.corp.example.com:1234", want: "http://cache.corp.example.com:1234"},
	{env: "cache.corp.example.com", want: "http://cache.corp.example.com"},
	{env: "https://cache.corp.example.com", want: "https://cache.corp.example.com"},
	{env: "http://127.0.0.1:8080", want: "http://127.0.0.1:8080"},
	{env: "https://127.0.0.1:8080", want: "https://127.0.0.1:8080"},
	{want: "<nil>"},
	{noenv: "example.com", req: "http://example.com/", env: "proxy", want: "<nil>"},
	{noenv: ".example.com", req: "http://example.com/", env: "proxy", want: "<nil>"},
	{noenv: "ample.com", req: "http://example.com/", env: "proxy", want: "http://proxy"},
	{noenv: "example.com", req: "http://foo.example.com/", env: "proxy", want: "<nil>"},
	{noenv: ".foo.com", req: "http://example.com/", env: "proxy", want: "http://proxy"},
}

func TestProxyFromEnvironment(t *testing.T) {
	os.Setenv("HTTP_PROXY", "")
	os.Setenv("http_proxy", "")
	os.Setenv("NO_PROXY", "")
	os.Setenv("no_proxy", "")
	for _, tt := range proxyFromEnvTests {
		os.Setenv("HTTP_PROXY", tt.env)
		os.Setenv("NO_PROXY", tt.noenv)
		reqURL := tt.req
		if reqURL == "" {
			reqURL = "http://example.com"
		}
		req, _ := NewRequest("GET", reqURL, nil)
		url, err := ProxyFromEnvironment(req)
		if g, e := fmt.Sprintf("%v", err), fmt.Sprintf("%v", tt.wanterr); g != e {
			t.Errorf("%v: got error = %q, want %q", tt, g, e)
			continue
		}
		if got := fmt.Sprintf("%s", url); got != tt.want {
			t.Errorf("%v: got URL = %q, want %q", tt, url, tt.want)
		}
	}
}

func TestIdleConnChannelLeak(t *testing.T) {
	var mu sync.Mutex
	var n int

	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
		mu.Lock()
		n++
		mu.Unlock()
	}))
	defer ts.Close()

	tr := &Transport{
		Dial: func(netw, addr string) (net.Conn, error) {
			return net.Dial(netw, ts.Listener.Addr().String())
		},
	}
	defer tr.CloseIdleConnections()

	c := &Client{Transport: tr}

	// First, without keep-alives.
	for _, disableKeep := range []bool{true, false} {
		tr.DisableKeepAlives = disableKeep
		for i := 0; i < 5; i++ {
			_, err := c.Get(fmt.Sprintf("http://foo-host-%d.tld/", i))
			if err != nil {
				t.Fatal(err)
			}
		}
		if got := tr.IdleConnChMapSizeForTesting(); got != 0 {
			t.Fatalf("ForDisableKeepAlives = %v, map size = %d; want 0", disableKeep, got)
		}
	}
}

// Verify the status quo: that the Client.Post function coerces its
// body into a ReadCloser if it's a Closer, and that the Transport
// then closes it.
func TestTransportClosesRequestBody(t *testing.T) {
	defer afterTest(t)
	ts := httptest.NewServer(http.HandlerFunc(func(w ResponseWriter, r *Request) {
		io.Copy(ioutil.Discard, r.Body)
	}))
	defer ts.Close()

	tr := &Transport{}
	defer tr.CloseIdleConnections()
	cl := &Client{Transport: tr}

	closes := 0

	res, err := cl.Post(ts.URL, "text/plain", countCloseReader{&closes, strings.NewReader("hello")})
	if err != nil {
		t.Fatal(err)
	}
	res.Body.Close()
	if closes != 1 {
		t.Errorf("closes = %d; want 1", closes)
	}
}

type countCloseReader struct {
	n *int
	io.Reader
}

func (cr countCloseReader) Close() error {
	(*cr.n)++
	return nil
}

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var rgz = []byte{
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}