tests: clean up output

Some document improvements and add a few more tests.

middleware/file/reload_test.go

@@ -2,6 +2,7 @@ package file
 
 import (
 	"io/ioutil"
+	"log"
 	"os"
 	"testing"
 	"time"
@@ -11,6 +12,8 @@ import (
 )
 
 func TestZoneReload(t *testing.T) {
+	log.SetOutput(ioutil.Discard)
+
 	fileName, rm, err := test.TempFile(".", reloadZoneTest)
 	if err != nil {
 		t.Fatalf("failed to create zone: %s", err)