test: Wait for iper3 server

Turns out that iperf3 is using the `simple` service type:

    $ sudo systemctl show iperf3 | grep ^Type=
    Type=simple

In this case `systemctl start iperf3` does not wait for the service to
signal that it is ready to handle requests or has finished initializing,
so we may return before the service is ready to serve requests.

We wait now until iperf3 port is in listening state.

Signed-off-by: Nir Soffer <nirsof@gmail.com>

Author: nirs

.github/workflows/lima.yaml

@@ -65,6 +65,14 @@ jobs:
           limactl shell vm1 sudo apt-get update
           limactl shell vm1 sudo apt-get install -y iperf3
           limactl shell vm1 sudo systemctl start iperf3.service
+          echo "Waiting for iperf3 server ..."
+          limactl shell vm1 bash -s << EOF
+            if ! timeout 10s bash -c "until ss -tln | grep -q :5201; do sleep 1; done"; then
+              echo >&2 "Timeout waiting for iperf3 port"
+              exit 1
+            fi
+          EOF
+          echo "iperf3 server is ready"
       - name: "Lima: vm1: get the IP"
         run: |
           limactl shell vm1 ip -4 -json addr show dev lima0 | jq -r .[0].addr_info[0].local | tee /tmp/vm1_iP