test: Cycle 23 — conditional send, multi-page memory, 500-message sustained load

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

crates/wasm-actor/tests/wasm_actor.rs

@@ -3779,3 +3779,136 @@ fn build_many_actors_from_same_bytes_sequentially() {
         rt.tick();
     }
 }
+
+// ── Guest that only sends on even-numbered messages ─────────────────────────
+
+#[test]
+fn guest_conditional_send_based_on_message_content() {
+    // Guest only sends a reply if the first byte of payload (after the 32-byte
+    // address) is even. Tests that the outbox is correctly empty when the guest
+    // decides not to send.
+    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 256)
+            (func (export "handle") (param $ptr i32) (param $len i32)
+                ;; Check if byte at ptr+32 (first payload byte) is even
+                local.get $ptr
+                i32.const 32
+                i32.add
+                i32.load8_u
+                i32.const 2
+                i32.rem_u
+                i32.const 0
+                i32.eq
+                if
+                    ;; Even: send reply
+                    local.get $ptr
+                    local.get $ptr
+                    i32.const 32
+                    i32.add
+                    local.get $len
+                    i32.const 32
+                    i32.sub
+                    call $send
+                end
+                ;; Odd: do nothing (empty outbox)
+            )
+        )
+    "#;
+    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 inbox = rt.new_inbox::<ByteMessage>().unwrap();
+    let addr = rt.spawn(actor).unwrap();
+
+    // Send even byte (0) — should get reply
+    rt.send_to(addr, framed_msg(inbox.addr(), &[0])).unwrap();
+    rt.tick();
+    assert!(inbox.try_recv().is_some(), "even byte should trigger reply");
+
+    // Send odd byte (1) — no reply
+    rt.send_to(addr, framed_msg(inbox.addr(), &[1])).unwrap();
+    rt.tick();
+    assert!(inbox.try_recv().is_none(), "odd byte should not trigger reply");
+
+    // Send even byte (2) — should get reply
+    rt.send_to(addr, framed_msg(inbox.addr(), &[2])).unwrap();
+    rt.tick();
+    assert!(inbox.try_recv().is_some(), "even byte should trigger reply");
+}
+
+// ── Guest with multiple memory pages ────────────────────────────────────────
+
+#[test]
+fn guest_with_multiple_initial_pages_works() {
+    // Module starts with 4 pages (256KiB). Alloc returns pointer in page 3.
+    let wat = r#"
+        (module
+            (import "swactor" "send" (func $send (param i32 i32 i32)))
+            (memory (export "memory") 4)  ;; 4 pages = 262144 bytes
+            (func (export "alloc") (param i32) (result i32)
+                i32.const 196608  ;; page 3 start (3 * 65536)
+            )
+            (func (export "handle") (param $ptr i32) (param $len i32)
+                ;; Echo from page 3
+                local.get $ptr
+                local.get $ptr
+                i32.const 32
+                i32.add
+                local.get $len
+                i32.const 32
+                i32.sub
+                call $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 inbox = rt.new_inbox::<ByteMessage>().unwrap();
+    let addr = rt.spawn(actor).unwrap();
+
+    let payload = b"multi-page";
+    rt.send_to(addr, framed_msg(inbox.addr(), payload)).unwrap();
+    rt.tick();
+
+    let received = inbox.try_recv().expect("multi-page alloc should work");
+    assert_eq!(received.0, payload);
+}
+
+// ── Long-running: echo actor processes 500 messages sequentially ────────────
+
+#[test]
+fn echo_processes_500_sequential_messages() {
+    // Sustained message processing without crashes, allocator exhaustion
+    // handling, and verified actor survival throughout.
+    let engine = SharedEngine::new().unwrap();
+    let actor = WasmActorBuilder::new(engine, guest_wasm("echo"))
+        .build()
+        .unwrap();
+
+    let rt = Runtime::new(RuntimeConfig::default());
+    let inbox = rt.new_inbox::<ByteMessage>().unwrap();
+    let addr = rt.spawn(actor).unwrap();
+
+    let mut received_count = 0;
+    for i in 0u16..500 {
+        let payload = i.to_le_bytes();
+        rt.send_to(addr, framed_msg(inbox.addr(), &payload)).unwrap();
+        rt.tick();
+        if let Some(msg) = inbox.try_recv() {
+            assert_eq!(msg.0, payload, "payload integrity at message {i}");
+            received_count += 1;
+        }
+    }
+
+    // With 65536-byte allocator and ~40 bytes per alloc (34 + alignment),
+    // all 500 messages should fit. Verify all echoed correctly.
+    assert_eq!(received_count, 500, "all 500 messages should echo");
+}