system-traffic.at: avoid a race condition on monitor log

Rather than letting the test framework kill any remaining ofctl monitor,
ask and wait for it to gracefully exit before looking at the log file.
This solves random failures of tests 29, 30 and 50.

Signed-off-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

tests/system-traffic.at

@@ -563,8 +563,6 @@ AT_CHECK([ovs-ofctl add-tlv-map br0 "{class=0xffff,type=0,len=4}->tun_metadata0"
 AT_CHECK([ovs-ofctl add-flows br0 flows.txt])
 AT_CHECK([ovs-ofctl add-flow br-underlay "actions=normal"])
 
-AT_CHECK([ovs-ofctl monitor br0 resume --detach --no-chdir --pidfile=ovs-ofctl0.pid 2> ofctl_monitor0.log])
-
 NS_CHECK_EXEC([at_ns0], [ping -q -c 3 10.1.1.100 | FORMAT_PING], [0], [dnl
 3 packets transmitted, 3 received, 0% packet loss, time 0ms
 ])
@@ -902,6 +900,8 @@ NS_CHECK_EXEC([at_ns0], [ping -q -c 3 -i 0.3 -w 2 10.1.1.2 | FORMAT_PING], [0],
 3 packets transmitted, 3 received, 0% packet loss, time 0ms
 ])
 
+OVS_APP_EXIT_AND_WAIT([ovs-ofctl])
+
 AT_CHECK([cat ofctl_monitor.log | STRIP_MONITOR_CSUM], [0], [dnl
 icmp,vlan_tci=0x0000,dl_src=ae:c6:7e:54:8d:4d,dl_dst=50:54:00:00:00:0b,nw_src=10.1.1.2,nw_dst=192.168.4.4,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=0,icmp_code=0 icmp_csum: <skip>
 icmp,vlan_tci=0x0000,dl_src=ae:c6:7e:54:8d:4d,dl_dst=50:54:00:00:00:0b,nw_src=10.1.1.2,nw_dst=192.168.4.4,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=0,icmp_code=0 icmp_csum: <skip>
@@ -1349,6 +1349,8 @@ AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 1 ct\(commit\),controller '5054
 dnl Now try a reply from port 2.
 AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 2 ct\(table=0\) '50540000000a50540000000908004500001c000000000011a4cd0a0101020a0101010002000100080000'])
 
+OVS_APP_EXIT_AND_WAIT([ovs-ofctl])
+
 dnl Check this output. We only see the latter two packets, not the first.
 AT_CHECK([cat ofctl_monitor.log], [0], [dnl
 NXT_PACKET_IN2 (xid=0x0): total_len=42 in_port=1 (via action) data_len=42 (unbuffered)
@@ -1395,6 +1397,8 @@ AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 "in_port=2 packet=50540000000a5
 
 AT_CHECK([ovs-appctl revalidator/purge], [0])
 
+OVS_APP_EXIT_AND_WAIT([ovs-ofctl])
+
 dnl Check this output. We only see the latter two packets, not the first.
 AT_CHECK([cat ofctl_monitor.log], [0], [dnl
 NXT_PACKET_IN2 (xid=0x0): cookie=0x0 total_len=42 in_port=1 (via action) data_len=42 (unbuffered)
@@ -2325,6 +2329,8 @@ AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 1 resubmit\(,0\) 'c6f94ecb72dbe
 dnl 3. Send an ICMP port unreach reply from a path midpoint for port 5555, related to the first packet
 AT_CHECK([ovs-ofctl -O OpenFlow13 packet-out br0 2 resubmit\(,0\) 'e64c473528c9c6f94ecb72db080045c0003d2e8700004001f354ac100003ac1000010303553f0000000045000021317040004011b138ac100001ac100002a28e15b3000d20966369616f0a'])
 
+OVS_APP_EXIT_AND_WAIT([ovs-ofctl])
+
 dnl Check this output. We only see the latter two packets, not the first.
 AT_CHECK([cat ofctl_monitor.log | grep -v ff02 | grep -v fe80 | grep -v no_match], [0], [dnl
 NXT_PACKET_IN2 (xid=0x0): table_id=1 cookie=0x0 total_len=75 ct_state=inv|trk,ip,in_port=2 (via action) data_len=75 (unbuffered)