http: make tests quiet, fixing a test race

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4754044

diff --git a/src/pkg/http/serve_test.go b/src/pkg/http/serve_test.go
index 55a9cbf70d55ca1195841bc6f340e0aa7959c9a5..2ba4a168bc5d8ba6c0a563b15d13dff1a98d97e4 100644 (file)
--- a/src/pkg/http/serve_test.go
+++ b/src/pkg/http/serve_test.go
@@ -110,7 +110,6 @@ func TestConsumingBodyOnNextConn(t *testing.T) {
        listener := &oneConnListener{conn}
        handler := func(res ResponseWriter, req *Request) {
                reqNum++
-               t.Logf("Got request #%d: %v", reqNum, req)
                ch <- req
        }
 
@@ -119,7 +118,6 @@ func TestConsumingBodyOnNextConn(t *testing.T) {
        }()
 
        var req *Request
-       t.Log("Waiting for first request.")
        req = <-ch
        if req == nil {
                t.Fatal("Got nil first request.")
@@ -129,7 +127,6 @@ func TestConsumingBodyOnNextConn(t *testing.T) {
                        req.Method, "POST")
        }
 
-       t.Log("Waiting for second request.")
        req = <-ch
        if req == nil {
                t.Fatal("Got nil first request.")
@@ -139,7 +136,6 @@ func TestConsumingBodyOnNextConn(t *testing.T) {
                        req.Method, "POST")
        }
 
-       t.Log("Waiting for EOF.")
        if serveerr := <-servech; serveerr != os.EOF {
                t.Errorf("Serve returned %q; expected EOF", serveerr)
        }
@@ -788,7 +784,24 @@ func TestZeroLengthPostAndResponse(t *testing.T) {
 }
 
 func TestHandlerPanic(t *testing.T) {
-       log.SetOutput(ioutil.Discard) // is noisy otherwise
+       // 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(HandlerFunc(func(ResponseWriter, *Request) {
@@ -799,6 +812,25 @@ func TestHandlerPanic(t *testing.T) {
        if err == nil {
                t.Logf("expected an error")
        }
+
+       // 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)
+       go func() {
+               buf := make([]byte, 1024)
+               _, err := pr.Read(buf)
+               if err != nil {
+                       t.Fatal(err)
+               }
+               done <- true
+       }()
+       select {
+       case <-done:
+               return
+       case <-time.After(5e9):
+               t.Error("expected server handler to log an error")
+       }
 }
 
 func TestNoDate(t *testing.T) {