cmd/peer: Refactor and test processing of response

cmd/peer/watch.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"os"
 
 	peerpb "github.com/cilium/cilium/api/v1/peer"
 	"github.com/cilium/hubble/cmd/common/config"
@@ -58,11 +59,7 @@ func runWatch(ctx context.Context, client peerpb.PeerClient) error {
 		case io.EOF, context.Canceled:
 			return nil
 		case nil:
-			tlsServerName := ""
-			if tls := resp.GetTls(); tls != nil {
-				tlsServerName = fmt.Sprintf(" (TLS.ServerName: %s)", tls.GetServerName())
-			}
-			fmt.Printf("%-12s %s %s%s\n", resp.GetType(), resp.GetAddress(), resp.GetName(), tlsServerName)
+			processResponse(os.Stdout, resp)
 		default:
 			if status.Code(err) == codes.Canceled {
 				return nil
@@ -71,3 +68,11 @@ func runWatch(ctx context.Context, client peerpb.PeerClient) error {
 		}
 	}
 }
+
+func processResponse(w io.Writer, resp *peerpb.ChangeNotification) {
+	tlsServerName := ""
+	if tls := resp.GetTls(); tls != nil {
+		tlsServerName = fmt.Sprintf(" (TLS.ServerName: %s)", tls.GetServerName())
+	}
+	_, _ = fmt.Fprintf(w, "%-12s %s %s%s\n", resp.GetType(), resp.GetAddress(), resp.GetName(), tlsServerName)
+}

cmd/peer/watch_test.go

@@ -0,0 +1,61 @@
+// Copyright 2021 Authors of Hubble
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package peer
+
+import (
+	"bytes"
+	"testing"
+
+	peerpb "github.com/cilium/cilium/api/v1/peer"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_processResponse(t *testing.T) {
+	var testCases = []struct {
+		name               string
+		changeNotification *peerpb.ChangeNotification
+		expectedOutput     string
+	}{
+		{
+			name: "happy path with tls",
+			changeNotification: &peerpb.ChangeNotification{
+				Name:    "foo.bar",
+				Address: "1.2.3.4",
+				Type:    peerpb.ChangeNotificationType_PEER_ADDED,
+				Tls:     &peerpb.TLS{ServerName: "tls.foo.bar"},
+			},
+			expectedOutput: "PEER_ADDED   1.2.3.4 foo.bar (TLS.ServerName: tls.foo.bar)\n",
+		},
+		{
+			name: "happy path with no tls",
+			changeNotification: &peerpb.ChangeNotification{
+				Name:    "foo.bar",
+				Address: "1.2.3.4",
+				Type:    peerpb.ChangeNotificationType_PEER_ADDED,
+			},
+			expectedOutput: "PEER_ADDED   1.2.3.4 foo.bar\n",
+		},
+		{
+			name:           "sad path with unknown change notification",
+			expectedOutput: "UNKNOWN       \n",
+		},
+	}
+
+	for _, tc := range testCases {
+		buf := bytes.Buffer{}
+		processResponse(&buf, tc.changeNotification)
+		assert.Equal(t, tc.expectedOutput, buf.String(), tc.name)
+	}
+}