fix compose test flake

Reading from the nc socket is flaky because docker-compose only starts
the containers. We cannot know at this point if the container did already
send the message. Give the container 5 seconds time to send the message
to prevent flakes.

This happened rarely with compose v1 but it looks like it will happen a
lot more with compose v2.

Example failure log:
https://storage.googleapis.com/cirrus-ci-6707778565701632-fcae48/artifacts/containers/podman/6567556239589376/html/compose_v2-podman-fedora-35-rootless-host.log.html

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/test/compose/slirp4netns_opts/tests.sh b/test/compose/slirp4netns_opts/tests.sh
index 1efce45c4..cfa84e1e4 100644
--- a/test/compose/slirp4netns_opts/tests.sh
+++ b/test/compose/slirp4netns_opts/tests.sh
@@ -3,4 +3,18 @@
 output="$(cat $OUTFILE)"
 expected="teststring"
 
+# Reading from the nc socket is flaky because docker-compose only starts
+# the containers. We cannot know at this point if the container did already
+# send the message. Give the container 5 seconds time to send the message
+# to prevent flakes.
+local _timeout=5
+while [ $_timeout -gt 0 ]; do
+    if [ -n "$output" ]; then
+        break
+    fi
+    sleep 1
+    _timeout=$(($_timeout - 1))
+    output="$(cat $OUTFILE)"
+done
+
 is "$output" "$expected" "$testname : nc received teststring"