netboot/pcap/writer_test.go
David Anderson e8185cf62d Use cmp.Diff to compare pcap packets.
This fixes a spurious failure from reflect.DeepEqual.
2017-12-24 17:22:09 -08:00

94 lines
2.2 KiB
Go

// Copyright 2016 Google Inc.
//
// 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 pcap
import (
"bytes"
"encoding/binary"
"testing"
"time"
"github.com/google/go-cmp/cmp"
)
func TestReadback(t *testing.T) {
pkts := []*Packet{
{
Timestamp: time.Now(),
Length: 42,
Bytes: []byte{1, 2, 3, 4},
},
{
Timestamp: time.Now(),
Length: 30,
Bytes: []byte{2, 3, 4, 5},
},
{
Timestamp: time.Now(),
Length: 20,
Bytes: []byte{3, 4, 5, 6},
},
{
Timestamp: time.Now(),
Length: 10,
Bytes: []byte{4, 5, 6, 7},
},
}
serializations := map[string]bool{}
for _, order := range []binary.ByteOrder{nil, binary.LittleEndian, binary.BigEndian} {
var b bytes.Buffer
w := &Writer{
Writer: &b,
LinkType: LinkEthernet,
SnapLen: 65535,
ByteOrder: order,
}
for _, pkt := range pkts {
if err := w.Put(pkt); err != nil {
t.Fatalf("Writing packet %#v: %s", pkt, err)
}
}
// Record the binary form, to check how many different serializations we get.
serializations[b.String()] = true
readBack := []*Packet{}
r, err := NewReader(&b)
if err != nil {
t.Fatalf("Initializing reader for writer read-back: %s", err)
}
if r.LinkType != LinkEthernet {
t.Fatalf("Wrote link type %d, read back %d", LinkEthernet, r.LinkType)
}
for r.Next() {
readBack = append(readBack, r.Packet())
}
if r.Err() != nil {
t.Fatalf("Reading packets back: %s", r.Err())
}
if diff := cmp.Diff(pkts, readBack); diff != "" {
t.Fatalf("Packets mutated by write-then-read (-want +got):\n%s", diff)
}
}
if len(serializations) != 2 {
t.Fatalf("Expected 2 distinct serializations due to endianness, got %d", len(serializations))
}
}