plugin/forward: add REFUSED test (#1878)

add a test to see if we copy the rcode correctly. Some minor cleanup in
import ordering and renaming NewUpstream to New as we already are in the
upstream package.

plugin/proxy/proxy_test.go

@@ -9,7 +9,12 @@ import (
 	"testing"
 	"time"
 
+	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/test"
+	"github.com/coredns/coredns/request"
+
 	"github.com/mholt/caddy/caddyfile"
+	"github.com/miekg/dns"
 )
 
 func TestStop(t *testing.T) {
@@ -70,3 +75,25 @@ func TestStop(t *testing.T) {
 		})
 	}
 }
+
+func TestProxyRefused(t *testing.T) {
+	s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
+		ret := new(dns.Msg)
+		ret.SetReply(r)
+		ret.Rcode = dns.RcodeRefused
+		w.WriteMsg(ret)
+	})
+	defer s.Close()
+
+	p := NewLookup([]string{s.Addr})
+
+	state := request.Request{W: &test.ResponseWriter{}, Req: new(dns.Msg)}
+	state.Req.SetQuestion("example.org.", dns.TypeA)
+	resp, err := p.Forward(state)
+	if err != nil {
+		t.Fatal("Expected to receive reply, but didn't")
+	}
+	if resp.Rcode != dns.RcodeRefused {
+		t.Errorf("Expected rcode to be %d, got %d", dns.RcodeRefused, resp.Rcode)
+	}
+}