update_sender_test.go

				0x00, 0x00, // Total Path Attribute Length
			},
			expectedError: nil,
		},
		{
			name:          "Normal withdraw without ADD-PATH",
			afi:           packet.IPv4AFI,
			multiProtocol: false,
			addPathTX:     false,
			prefix:        bnet.NewPfx(bnet.IPv4(1413010532), 24),
			path: &route.Path{
				Type: route.BGPPathType,
				BGPPath: &route.BGPPath{
					PathIdentifier: 1,
				},
			},
			expected: []byte{
				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // BGP Marker
				0x00, 0x1b, // BGP Message Length
				0x02,       // BGP Message Type == Update
				0x00, 0x04, // WithDraw Octet length
				0x18,             // Prefix Length
				0x54, 0x38, 0xd4, // Prefix,
				0x00, 0x00, // Total Path Attribute Length
			},
			expectedError: nil,
		},
		{
			name:          "IPv6 MP_UNREACH_NLRI",
			afi:           packet.IPv6AFI,
			multiProtocol: true,
			addPathTX:     false,
			prefix:        bnet.NewPfx(bnet.IPv6FromBlocks(0x2804, 0x148c, 0, 0, 0, 0, 0, 0), 32),
			path: &route.Path{
				Type:    route.BGPPathType,
				BGPPath: &route.BGPPath{},
			},
			expected: []byte{
				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // BGP Marker
				0x00, 0x22, // BGP Message Length
				0x02,       // BGP Message Type == Update
				0x00, 0x00, // WithDraw Octet length
				0x00, 0x0b, // Length
				0x80,       // Flags
				0x0f,       // Attribute Code
				0x08,       // Attribute length
				0x00, 0x02, // AFI
				0x01,                         // SAFI
				0x20, 0x28, 0x04, 0x14, 0x8c, // Prefix
			},
		},
		{
			name:          "IPv6 MP_UNREACH_NLRI with ADD-PATH",
			afi:           packet.IPv6AFI,
			multiProtocol: true,
			addPathTX:     true,
			prefix:        bnet.NewPfx(bnet.IPv6FromBlocks(0x2804, 0x148c, 0, 0, 0, 0, 0, 0), 32),
			path: &route.Path{
				Type: route.BGPPathType,
				BGPPath: &route.BGPPath{
					PathIdentifier: 100,
				},
			},
			expected: []byte{
				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, // BGP Marker
				0x00, 0x26, // BGP Message Length
				0x02,       // BGP Message Type == Update
				0x00, 0x00, // WithDraw Octet length
				0x00, 0x0f, // Length
				0x80,       // Flags
				0x0f,       // Attribute Code
				0x0c,       // Attribute length
				0x00, 0x02, // AFI
				0x01,                  // SAFI
				0x00, 0x00, 0x00, 100, // Path Identifier
				0x20, 0x28, 0x04, 0x14, 0x8c, // Prefix
			},
		},
		{
			name:          "IPv6 MP_UNREACH_NLRI without multi protocol beeing negotiated",
			afi:           packet.IPv6AFI,
			multiProtocol: false,
			addPathTX:     false,
			prefix:        bnet.NewPfx(bnet.IPv6FromBlocks(0x2804, 0x148c, 0, 0, 0, 0, 0, 0), 32),
			path: &route.Path{
				Type: route.BGPPathType,
				BGPPath: &route.BGPPath{
					PathIdentifier: 1,
				},
			},
			expected:      []byte{},
			expectedError: errors.New("IPv6 was not negotiated"),
		},
	}

	t.Parallel()

	for _, tc := range testcases {
		t.Run(tc.name, func(t *testing.T) {
			buf := bytes.NewBuffer([]byte{})

			u := &UpdateSender{
				fsm: &FSM{},
				addressFamily: &fsmAddressFamily{
					addPathTX:     tc.addPathTX,
					multiProtocol: tc.multiProtocol,
					afi:           tc.afi,
					safi:          packet.UnicastSAFI,
				},
				options: &packet.EncodeOptions{
					UseAddPath: tc.addPathTX,
				},
			}

			err := u.withdrawPrefix(buf, tc.prefix, tc.path)
			assert.Equal(t, tc.expectedError, err, "error mismatch")
			assert.Equal(t, tc.expected, buf.Bytes(), "expected different bytes")
		})
	}
}