// 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 (
	"bytes"
	"compress/gzip"
	"crypto/rand"
	"fmt"
	"io"
	"io/ioutil"
	. "net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"runtime"
	"strconv"
	"strings"
	"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))
})

// 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) {
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	for _, disableKeepAlive := range []bool{false, true} {
		tr := &Transport{DisableKeepAlives: disableKeepAlive}
		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) {
	ts := httptest.NewServer(hostPortHandler)
	defer ts.Close()

	for _, connectionClose := range []bool{false, true} {
		tr := &Transport{}
		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)
			}
			body, err := ioutil.ReadAll(res.Body)
			defer res.Body.Close()
			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)
		}
	}
}

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

	for _, connectionClose := range []bool{false, true} {
		tr := &Transport{}
		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)
		}
	}
}

func TestTransportIdleCacheKeys(t *testing.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) {
	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 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) {
	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) {
	if testing.Short() {
		t.Logf("skipping test in short mode")
		return
	}
	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) {
	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)
		}
		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(0), res.ContentLength; e != g {
			t.Errorf("loop %d: expected res.ContentLength of %v, got %v", i, e, g)
		}
	}
}

// TestTransportHeadChunkedResponse verifies that we ignore chunked transfer-encoding
// on responses to HEAD requests.
func TestTransportHeadChunkedResponse(t *testing.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) {
	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 {
			gzip, err := gzip.NewReader(res.Body)
			if err != nil {
				t.Errorf("%d. gzip NewReader: %v", i, err)
				continue
			}
			body, err = ioutil.ReadAll(gzip)
			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) {
	const testString = "The test string aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
	const nRandBytes = 1024 * 1024
	ts := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, req *Request) {
		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")
		if req.Method == "HEAD" {
			return
		}

		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) {
	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) {
	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) {
	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")
	}
}

// This used to crash; http://golang.org/issue/3266
func TestTransportIdleConnCrash(t *testing.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
}

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) {
	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)
	}
}

var proxyFromEnvTests = []struct {
	env     string
	wanturl string
	wanterr error
}{
	{"127.0.0.1:8080", "http://127.0.0.1:8080", nil},
	{"http://127.0.0.1:8080", "http://127.0.0.1:8080", nil},
	{"https://127.0.0.1:8080", "https://127.0.0.1:8080", nil},
	{"", "<nil>", nil},
}

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

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