Add port monitoring test script

hack/bats/extras/port-monitor.bats

@@ -0,0 +1,68 @@
+# SPDX-FileCopyrightText: Copyright The Lima Authors
+# SPDX-License-Identifier: Apache-2.0
+
+# This test verifies that when a container is destroyed, its ports can be reused
+# immediately and are not subject to being freed by a polling loop. See #4066.
+
+# This test should not be run in CI as it is not totally reliable: there is always a chance that the server will
+# take longer to actually respond to requests after opening the port. The test works around it by retrying once
+# on curl exit code 52, but have been observed at least once to fail by refusing to connect.
+
+load "../helpers/load"
+
+: "${TEMPLATE:=default}" # Alternative: "docker"
+
+NAME=nginx
+
+local_setup_file() {
+    limactl delete --force "$NAME" || :
+    limactl start --yes --name "$NAME" --mount "$BATS_TMPDIR" "template://${TEMPLATE}" 3>&- 4>&-
+}
+
+local_teardown_file() {
+    limactl delete --force "$NAME"
+}
+
+ctrctl() {
+    if [[ $(limactl ls "$NAME" --yq .config.containerd.user) == true ]]; then
+        limactl shell $NAME nerdctl "$@"
+    else
+        limactl shell $NAME docker "$@"
+    fi
+}
+
+nginx_start() {
+    echo "$COUNTER" >"${BATS_TEST_TMPDIR}/index.html"
+    ctrctl run -d --name nginx -p 8080:80 -v "${BATS_TEST_TMPDIR}:/usr/share/nginx/html:ro" nginx
+}
+
+nginx_stop() {
+    ctrctl stop nginx
+    ctrctl rm nginx
+}
+
+verify_port() {
+    run curl --silent http://127.0.0.1:8080
+    # If nginx is not quite ready and doesn't send any response at all, give it one extra chance
+    if [[ $status -eq 52 ]]; then
+        sleep 0.5
+        run curl --silent http://127.0.0.1:8080
+    fi
+    assert_success
+    assert_output "$COUNTER"
+}
+
+@test 'Verify that the container is working' {
+    COUNTER=0
+    ctrctl pull --quiet nginx
+    nginx_start
+    verify_port
+}
+
+@test 'Stop and restart the container multiple times' {
+    for COUNTER in {1..100}; do
+        nginx_stop
+        nginx_start
+        verify_port
+    done
+}