test: Cycle 17 — truncated WASM, no-import module, 4-thread stress, i32::MIN, dual watcher

Authored by Claude, lovingly guided by Zachery Aaron Shores-Chmielewski

crates/wasm-actor/tests/wasm_actor.rs

@@ -3014,3 +3014,173 @@ fn alloc_alternates_between_failure_and_success() {
 
     assert_eq!(echoed, 3, "should echo on even-numbered alloc calls only");
 }
+
+// ── Truncated WASM: module bytes cut mid-section ────────────────────────────
+
+#[test]
+fn truncated_wasm_bytes_returns_error() {
+    // Take a valid WASM module and truncate it. Should fail to compile.
+    let valid_wasm = guest_wasm("echo");
+    let truncated = valid_wasm[..valid_wasm.len() / 2].to_vec();
+
+    let engine = SharedEngine::new().unwrap();
+    let result = WasmActorBuilder::new(engine, truncated).build();
+    assert!(result.is_err(), "truncated WASM should fail to compile");
+}
+
+// ── Module with no import of swactor.send: handle that never sends ──────────
+
+#[test]
+fn module_without_send_import_can_still_process_messages() {
+    // A module that doesn't import swactor.send at all.
+    // It should build successfully (linker defines send but module doesn't import it).
+    // Handle can process messages without sending.
+    let wat = r#"
+        (module
+            (memory (export "memory") 1)
+            (func (export "alloc") (param i32) (result i32) i32.const 256)
+            (func (export "handle") (param i32 i32)
+                ;; Process the message but never send anything
+                ;; (No import of swactor.send)
+            )
+        )
+    "#;
+    let wasm = wat::parse_str(wat).unwrap();
+    let engine = SharedEngine::new().unwrap();
+    let actor = WasmActorBuilder::new(engine, wasm).build().unwrap();
+
+    let rt = Runtime::new(RuntimeConfig::default());
+    let addr = rt.spawn(actor).unwrap();
+
+    rt.send_to(addr, ByteMessage(vec![1, 2, 3])).unwrap();
+    rt.tick();
+
+    // Actor processed message, didn't send anything, survives
+    rt.send_to(addr, ByteMessage(vec![4, 5, 6])).unwrap();
+    rt.tick();
+}
+
+// ── Multi-worker stress: 10 WASM actors on 4-thread runtime ─────────────────
+
+#[test]
+fn ten_wasm_actors_on_four_thread_runtime() {
+    // Spawn 10 WASM echo actors on a 4-thread runtime, send a message to each,
+    // and verify all responses arrive.
+    let engine = SharedEngine::new().unwrap();
+    let wasm_bytes = guest_wasm("echo");
+
+    let config = RuntimeConfig {
+        num_threads: 4,
+        ..RuntimeConfig::default()
+    };
+    let rt = Runtime::new(config);
+    let inbox = rt.new_inbox::<ByteMessage>().unwrap();
+
+    let mut addrs = Vec::new();
+    for _ in 0..10 {
+        let actor = WasmActorBuilder::new(engine.clone(), wasm_bytes.clone())
+            .build()
+            .unwrap();
+        addrs.push(rt.spawn(actor).unwrap());
+    }
+
+    for (i, addr) in addrs.iter().enumerate() {
+        rt.send_to(*addr, framed_msg(inbox.addr(), &[i as u8])).unwrap();
+    }
+
+    let handle = rt.run().unwrap();
+
+    // Poll for all 10 responses
+    let mut received = Vec::new();
+    for _ in 0..40 {
+        std::thread::sleep(std::time::Duration::from_millis(25));
+        while let Some(msg) = inbox.try_recv() {
+            received.push(msg.0[0]);
+        }
+        if received.len() == 10 {
+            break;
+        }
+    }
+
+    handle.shutdown();
+
+    received.sort();
+    assert_eq!(received, (0..10u8).collect::<Vec<_>>(), "all 10 actors should echo");
+}
+
+// ── alloc with i32::MIN: most negative value ────────────────────────────────
+
+#[test]
+fn alloc_returns_i32_min_drops_message_actor_survives() {
+    let wat = r#"
+        (module
+            (import "swactor" "send" (func $send (param i32 i32 i32)))
+            (memory (export "memory") 1)
+            (func (export "alloc") (param i32) (result i32)
+                i32.const -2147483648  ;; i32::MIN
+            )
+            (func (export "handle") (param i32 i32))
+        )
+    "#;
+    let wasm = wat::parse_str(wat).unwrap();
+    let engine = SharedEngine::new().unwrap();
+    let actor = WasmActorBuilder::new(engine, wasm).build().unwrap();
+
+    let rt = Runtime::new(RuntimeConfig::default());
+    let addr = rt.spawn(actor).unwrap();
+
+    rt.send_to(addr, ByteMessage(vec![1])).unwrap();
+    rt.tick(); // ptr < 0 guard catches i32::MIN
+
+    rt.send_to(addr, ByteMessage(vec![2])).unwrap();
+    rt.tick();
+}
+
+// ── Watch integration: native watcher + WASM watcher observing same death ───
+
+struct DeathCounter {
+    count: std::sync::Arc<std::sync::atomic::AtomicUsize>,
+}
+
+#[derive(Clone)]
+struct WatchAddr(ActorAddress);
+
+impl ActorInterface for DeathCounter {
+    type Incoming = WatchAddr;
+    type Response = ();
+    fn handle(&mut self, ctx: &Ctx, msg: WatchAddr) {
+        ctx.watch(msg.0);
+    }
+    fn on_actor_exit(&mut self, _ctx: &Ctx, _exited: swactor::actor::ActorExited) {
+        self.count.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
+    }
+}
+
+#[test]
+fn two_watchers_both_notified_when_wasm_actor_dies() {
+    let engine = SharedEngine::new().unwrap();
+    let target = WasmActorBuilder::new(engine, guest_wasm("silent"))
+        .build()
+        .unwrap();
+
+    let rt = Runtime::new(RuntimeConfig::default());
+
+    let count_a = std::sync::Arc::new(std::sync::atomic::AtomicUsize::new(0));
+    let count_b = std::sync::Arc::new(std::sync::atomic::AtomicUsize::new(0));
+
+    let target_addr = rt.spawn(target).unwrap();
+    let watcher_a = rt.spawn(DeathCounter { count: count_a.clone() }).unwrap();
+    let watcher_b = rt.spawn(DeathCounter { count: count_b.clone() }).unwrap();
+
+    // Both watchers watch the target
+    rt.send_to(watcher_a, WatchAddr(target_addr)).unwrap();
+    rt.send_to(watcher_b, WatchAddr(target_addr)).unwrap();
+    for _ in 0..3 { rt.tick(); }
+
+    // Kill the target
+    rt.stop_actor(target_addr).unwrap();
+    for _ in 0..5 { rt.tick(); }
+
+    assert_eq!(count_a.load(std::sync::atomic::Ordering::SeqCst), 1, "watcher A should be notified");
+    assert_eq!(count_b.load(std::sync::atomic::Ordering::SeqCst), 1, "watcher B should be notified");
+}