[ovs-git] [ovn-org/ovn] 29b99b: tests: Fix inconsistent "ACL Conjunction" test.

[Mark Michelson]

  Branch: refs/heads/branch-21.03
  Home:   https://github.com/ovn-org/ovn
  Commit: 29b99bc7ad68f99d5c4b9a43728391cc6ee64f28
      https://github.com/ovn-org/ovn/commit/29b99bc7ad68f99d5c4b9a43728391cc6ee64f28
  Author: Mark Michelson <mmichels at redhat.com>
  Date:   2021-05-10 (Mon, 10 May 2021)

  Changed paths:
    M tests/ovn-macros.at
    M tests/ovn.at

  Log Message:
  -----------
  tests: Fix inconsistent "ACL Conjunction" test.

The ACL Conjunction test would occasionally fail during automated test
runs. During the test, we send a packet on a netdev-dummy interface and
check the associated pcap file to ensure the packet is sent where we
expect and that it has the expected contents. Looking at logs from
failed runs, it appeared that the pcap file was unpopulated. This likely
was because we were attempting to dump the contents of the pcap file
before the packet had been processed and added to the pcap file.

This patch aims to fix the problem by blocking until the pcap file has
been modified when sending the packet to the netdev-dummy interface.
Since this could be a useful thing for other tests, this new method of
blocking has been added to ovn-macros.at.

Signed-off-by: Mark Michelson <mmichels at redhat.com>