Add integration tests based on testcontainers

tests/testcontainers_wireguard.rs

@@ -0,0 +1,47 @@
+mod support;
+
+use std::time::Duration;
+
+use support::container_harness::{ProbeNames, cleanup_confirmed_probe_resources, run_probe};
+use support::container_selection::Selection;
+
+const CLEANUP_BUDGET: Duration = Duration::from_secs(40);
+
+#[test]
+#[ignore = "requires an explicitly selected disposable Docker daemon"]
+fn selected_daemon_wireguard_and_application_smoke() {
+    let selection = Selection::from_process_environment()
+        .unwrap_or_else(|category| panic!("Testcontainers selection failed ({category})"));
+    let names = ProbeNames::unique();
+    let result = run_probe(&names);
+
+    // run_probe is synchronous: all Testcontainers requests return or reach the
+    // pinned client's request timeout before this ownership-checked cleanup.
+    let cleanup = cleanup_confirmed_probe_resources(
+        &selection,
+        &names,
+        &std::process::id().to_string(),
+        CLEANUP_BUDGET,
+    );
+
+    if !cleanup.is_empty() {
+        eprintln!(
+            "Testcontainers cleanup incomplete for owned resources {}, {}, {}, {} ({})",
+            names.network,
+            names.server,
+            names.baseline,
+            names.client,
+            cleanup.join(", ")
+        );
+    }
+    if let Err(category) = result {
+        panic!("Testcontainers probe failed ({category})");
+    }
+    if !cleanup.is_empty() {
+        panic!("Testcontainers probe passed but owned-resource cleanup was incomplete");
+    }
+    eprintln!(
+        "Testcontainers capability and Application smoke passed; owned resources: {}, {}, {}, {}",
+        names.network, names.server, names.baseline, names.client
+    );
+}