% go test -race golang.org/x/net/context/ctxhttp
==================
WARNING: DATA RACE
Write by goroutine 14:
  sync.raceWrite()
      /usr/local/google/home/sameer/go/src/sync/race.go:41 +0x2e
  sync.(*WaitGroup).Wait()
      /usr/local/google/home/sameer/go/src/sync/waitgroup.go:124 +0xf9
  net/http/httptest.(*Server).Close()
      /usr/local/google/home/sameer/go/src/net/http/httptest/server.go:168 +0x80
  golang.org/x/net/context/ctxhttp.doRequest()
      /usr/local/google/home/sameer/gocode/src/golang.org/x/net/context/ctxhttp/ctxhttp_test.go:71 +0x129
  golang.org/x/net/context/ctxhttp.TestCancel()
      /usr/local/google/home/sameer/gocode/src/golang.org/x/net/context/ctxhttp/ctxhttp_test.go:37 +0x106
  testing.tRunner()
      /usr/local/google/home/sameer/go/src/testing/testing.go:456 +0xdc

Previous read by goroutine 20:
  sync.raceRead()
      /usr/local/google/home/sameer/go/src/sync/race.go:37 +0x2e
  sync.(*WaitGroup).Add()
      /usr/local/google/home/sameer/go/src/sync/waitgroup.go:66 +0xfa
  net/http/httptest.(*waitGroupHandler).ServeHTTP()
      /usr/local/google/home/sameer/go/src/net/http/httptest/server.go:198 +0x5c
  net/http.serverHandler.ServeHTTP()
      /usr/local/google/home/sameer/go/src/net/http/server.go:1816 +0x206
  net/http.(*conn).serve()
      /usr/local/google/home/sameer/go/src/net/http/server.go:1315 +0x117c

Goroutine 14 (running) created at:
  testing.RunTests()
      /usr/local/google/home/sameer/go/src/testing/testing.go:561 +0xaa3
  testing.(*M).Run()
      /usr/local/google/home/sameer/go/src/testing/testing.go:494 +0xe4
  main.main()
      golang.org/x/net/context/ctxhttp/_test/_testmain.go:58 +0x20f

Goroutine 20 (running) created at:
  net/http.(*Server).Serve()
      /usr/local/google/home/sameer/go/src/net/http/server.go:1864 +0x464
==================
PASS
Found 1 data race(s)
FAIL    golang.org/x/net/context/ctxhttp    1.339s