diff --git a/crates/wasm-actor/tests/wasm_actor.rs b/crates/wasm-actor/tests/wasm_actor.rs
index b5d9cc1..c18dfd0 100644
--- a/crates/wasm-actor/tests/wasm_actor.rs
+++ b/crates/wasm-actor/tests/wasm_actor.rs
@@ -6400,3 +6400,138 @@ fn fan_in_from_multiple_native_senders() {
         assert_eq!(msg.0, vec![i as u8], "inbox {i} should get correct payload");
     }
 }
+
+// ── Module with multiple functions calling each other ────────────────────────
+
+#[test]
+fn module_with_internal_function_calls() {
+    // Guest has helper functions called from handle.
+    let wat = r#"
+        (module
+            (import "swactor" "send" (func $send (param i32 i32 i32)))
+            (memory (export "memory") 1)
+            (func $double (param $x i32) (result i32)
+                (i32.mul (local.get $x) (i32.const 2))
+            )
+            (func $add_ten (param $x i32) (result i32)
+                (i32.add (local.get $x) (i32.const 10))
+            )
+            (func (export "alloc") (param i32) (result i32) i32.const 4096)
+            (func (export "handle") (param $ptr i32) (param $len i32)
+                ;; Read first payload byte, double it, add 10
+                (i32.store8 (i32.const 200)
+                    (call $add_ten
+                        (call $double
+                            (i32.load8_u (i32.add (local.get $ptr) (i32.const 32)))
+                        )
+                    )
+                )
+                (call $send (local.get $ptr) (i32.const 200) (i32.const 1))
+            )
+        )
+    "#;
+    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();
+
+    // input=5: double(5)=10, add_ten(10)=20
+    rt.send_to(addr, framed_msg(inbox.addr(), &[5])).unwrap();
+    // input=100: double(100)=200, add_ten(200)=210
+    rt.send_to(addr, framed_msg(inbox.addr(), &[100])).unwrap();
+    rt.tick();
+
+    let msg1 = inbox.try_recv().unwrap();
+    let msg2 = inbox.try_recv().unwrap();
+    assert_eq!(msg1.0[0], 20);
+    assert_eq!(msg2.0[0], 210);
+}
+
+// ── Build from pre-compiled WAT bytes (no guest dir needed) ─────────────────
+
+#[test]
+fn build_from_raw_wat_bytes() {
+    let wat = r#"
+        (module
+            (memory (export "memory") 1)
+            (func (export "alloc") (param i32) (result i32) i32.const 0)
+            (func (export "handle") (param i32 i32))
+        )
+    "#;
+    // Convert WAT → WASM at runtime
+    let wasm = wat::parse_str(wat).unwrap();
+    let engine = SharedEngine::new().unwrap();
+    let actor = WasmActorBuilder::new(engine, wasm).build().unwrap();
+
+    // Verify it works (silent actor — no sends)
+    let rt = Runtime::new(RuntimeConfig::default());
+    let inbox = rt.new_inbox::<ByteMessage>().unwrap();
+    let addr = rt.spawn(actor).unwrap();
+
+    rt.send_to(addr, framed_msg(inbox.addr(), b"silent")).unwrap();
+    rt.tick();
+    assert!(inbox.try_recv().is_none(), "silent actor should not send anything");
+}
+
+// ── Rapidly build and discard actors without spawning ────────────────────────
+
+#[test]
+fn build_and_discard_100_actors() {
+    // Build 100 actors but don't spawn them. Tests that WasmActor drops cleanly.
+    let engine = SharedEngine::new().unwrap();
+    for _ in 0..100 {
+        let actor = WasmActorBuilder::new(engine.clone(), guest_wasm("echo"))
+            .build()
+            .unwrap();
+        drop(actor);
+    }
+    // No panic = success
+}
+
+// ── Guest with f32/f64 floating point ops ───────────────────────────────────
+
+#[test]
+fn handle_uses_floating_point() {
+    // Guest performs f64 arithmetic and stores result as i32.
+    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 4096)
+            (func (export "handle") (param $ptr i32) (param $len i32)
+                ;; Compute floor(3.14 * 10) = floor(31.4) = 31
+                (i32.store8 (i32.const 200)
+                    (i32.trunc_f64_s
+                        (f64.mul (f64.const 3.14) (f64.const 10.0))
+                    )
+                )
+                (call $send (local.get $ptr) (i32.const 200) (i32.const 1))
+            )
+        )
+    "#;
+    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();
+
+    rt.send_to(addr, framed_msg(inbox.addr(), b"float")).unwrap();
+    rt.tick();
+
+    let msg = inbox.try_recv().unwrap();
+    assert_eq!(msg.0[0], 31, "floor(3.14 * 10) = 31");
+}
+
+// ── Empty WASM bytes produces error ─────────────────────────────────────────
+
+#[test]
+fn empty_wasm_bytes_error() {
+    let engine = SharedEngine::new().unwrap();
+    let result = WasmActorBuilder::new(engine, Vec::<u8>::new()).build();
+    assert!(result.is_err(), "empty bytes should fail");
+}