Coverage improvement in one package (#284)

* Make sure the Handler handles things correctly

logging/logging.go

@@ -3,6 +3,7 @@
 package logging
 
 import (
+	golog "log"
 	"net/http"
 	"os"
 
@@ -17,7 +18,7 @@ import (
 // when dockerising an Apache or Nginx instance.
 var Logger = log.Logger{
 	Handler: json.New(os.Stderr),
-	Level: log.DebugLevel,
+	Level:   log.DebugLevel,
 }
 
 // MakeAccessLogHandler wraps |handler| with another handler that logs
@@ -26,5 +27,5 @@ var Logger = log.Logger{
 // access logs, because access logs are a fairly standard format that
 // has been around for a long time now, so better to follow such standard.
 func MakeAccessLogHandler(handler http.Handler) http.Handler {
-	return handlers.LoggingHandler(os.Stdout, handler)
+	return handlers.LoggingHandler(golog.Writer(), handler)
 }

logging/logging_test.go

@@ -0,0 +1,40 @@
+package logging
+
+import (
+	"bytes"
+	"log"
+	"net/http"
+	"testing"
+
+	"github.com/m-lab/go/httpx"
+	"github.com/m-lab/go/rtx"
+)
+
+type fakeHandler struct{}
+
+func (s *fakeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(200)
+}
+
+func TestMakeAccessLogHandler(t *testing.T) {
+	buff := &bytes.Buffer{}
+	old := log.Writer()
+	defer func() {
+		log.SetOutput(old)
+	}()
+	log.SetOutput(buff)
+	f := MakeAccessLogHandler(&fakeHandler{})
+	log.SetOutput(old)
+	srv := http.Server{
+		Addr:    ":0",
+		Handler: f,
+	}
+	rtx.Must(httpx.ListenAndServeAsync(&srv), "Could not start server")
+	defer srv.Close()
+	_, err := http.Get("http://" + srv.Addr + "/")
+	rtx.Must(err, "Could not get")
+	s, err := buff.ReadString('\n')
+	if s == "" {
+		t.Error("We should not have had an empty string")
+	}
+}