Seen on master, commit cf7efe01e791fd1aa688624194e6e2ffffd8f97f

See the attached logs for details of what went wrong. Here's just a quick summary:

==============================================================================
IPv4 Test Case
==============================================================================
IPv4 FIB test FAIL [ temp dir used by test case: /tmp/vpp-unittest-TestIPv4-pEzkrr ]

==============================================================================
FAIL: IPv4 FIB test
------------------------------------------------------------------------------
Traceback (most recent call last):
File "/home/jlinkes/vpp/test/test_ip4.py", line 217, in test_fib
self.verify_capture(self.pg0, pkts)
File "/home/jlinkes/vpp/test/test_ip4.py", line 164, in verify_capture
self.assertTrue(Dot1Q not in packet)
AssertionError: False is not true

==============================================================================
IP4 VRF Multi-instance Test Case
==============================================================================
00:23:14,181 Unexpected or invalid packet:
###[ Ethernet ]###
dst = 02:03:00:00:ff:02
src = 02:fe:ec:14:f5:48
type = 0x800
###[ IP ]###
version = 4
ihl = 5
tos = 0x0
len = 494
id = 1
flags =
frag = 0
ttl = 63
proto = udp
chksum = 0x1cd9
src = 172.16.2.3
dst = 172.16.3.2
\options \
###[ UDP ]###
sport = 1234
dport = 1234
len = 474
chksum = 0x28db
###[ Raw ]###
load = '15 2 3 -1 -1 '

IP4 VRF Multi-instance test 1 - create 4 VRFs FAIL [ temp dir used by test case: /tmp/vpp-unittest-TestIp4VrfMultiInst-rFLPfA ]
00:23:16,827 Unexpected or invalid packet:
###[ Ethernet ]###
dst = 02:09:00:00:ff:02
src = 02:fe:70:03:5f:0e
type = 0x800
###[ IP ]###
version = 4
ihl = 5
tos = 0x0
len = 494
id = 1
flags =
frag = 0
ttl = 63
proto = udp
chksum = 0x10d7
src = 172.16.8.5
dst = 172.16.9.2
\options \
###[ UDP ]###
sport = 1234
dport = 1234
len = 474
chksum = 0x16cd
###[ Raw ]###
load = '75 8 9 -1 -1 '

IP4 VRF Multi-instance test 2 - reset 2 VRFs FAIL [ temp dir used by test case: /tmp/vpp-unittest-TestIp4VrfMultiInst-rFLPfA ]
00:23:20,042 Unexpected or invalid packet:
###[ Ethernet ]###
dst = 02:03:00:00:ff:02
src = 02:fe:ec:14:f5:48
type = 0x800
###[ IP ]###
version = 4
ihl = 5
tos = 0x0
len = 1500
id = 1
flags =
frag = 0
ttl = 63
proto = udp
chksum = 0x18ea
src = 172.16.2.4
dst = 172.16.3.2
\options \
###[ UDP ]###
sport = 1234
dport = 1234
len = 1480
chksum = 0x1df
###[ Raw ]###
load = '15 2 3 -1 -1 '

IP4 VRF Multi-instance 3 - add 2 VRFs FAIL [ temp dir used by test case: /tmp/vpp-unittest-TestIp4VrfMultiInst-rFLPfA ]
IP4 VRF Multi-instance test 4 - reset 4 VRFs OK

==============================================================================
FAIL: IP4 VRF Multi-instance test 1 - create 4 VRFs
------------------------------------------------------------------------------
Traceback (most recent call last):
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 437, in test_ip4_vrf_01
self.run_verify_test()
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 388, in run_verify_test
self.verify_capture(pg_if, capture)
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 301, in verify_capture
self.assertEqual(payload_info.dst, dst_sw_if_index)
AssertionError: 3 != 1

==============================================================================
FAIL: IP4 VRF Multi-instance test 2 - reset 2 VRFs
------------------------------------------------------------------------------
Traceback (most recent call last):
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 457, in test_ip4_vrf_02
self.run_verify_test()
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 388, in run_verify_test
self.verify_capture(pg_if, capture)
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 301, in verify_capture
self.assertEqual(payload_info.dst, dst_sw_if_index)
AssertionError: 9 != 7

==============================================================================
FAIL: IP4 VRF Multi-instance 3 - add 2 VRFs
------------------------------------------------------------------------------
Traceback (most recent call last):
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 477, in test_ip4_vrf_03
self.run_verify_test()
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 388, in run_verify_test
self.verify_capture(pg_if, capture)
File "/home/jlinkes/vpp/test/test_ip4_vrf_multi_instance.py", line 301, in verify_capture
self.assertEqual(payload_info.dst, dst_sw_if_index)