remove miniflare workaround

cloudflare/workers-sdk#13577 landed

Author: connyay

package-lock.json

@@ -15,7 +15,7 @@
   "homepage": "https://github.com/cloudflare/workers-rs#readme",
   "devDependencies": {
     "@types/node": "^24.0.1",
-    "miniflare": "^4.20260329.0",
+    "miniflare": "^4.20260420.0",
     "typescript": "^5.8.3",
     "uuid": "^11.1.0",
     "vitest": "^3.2.4"

package.json

@@ -13,13 +13,10 @@ async function runScenario(name: string): Promise<SendResult> {
   return (await resp.json()) as SendResult;
 }
 
-// Miniflare's send_email binding resolves to `undefined` on success rather
-// than `{ messageId }` like real workerd, so `messageId` is expected to be an
-// empty string here. We still assert the type/presence.
 function expectSuccess(result: SendResult) {
   expect(result.error).toBeNull();
   expect(result.ok).toBe(true);
-  expect(typeof result.messageId).toBe("string");
+  expect(result.messageId).toBeTruthy();
 }
 
 describe("send email (raw MIME)", () => {

test/tests/send_email.spec.ts

@@ -115,25 +115,16 @@ impl SendEmail {
     async fn send_js(&self, payload: &JsValue) -> Result<EmailSendResult> {
         let promise = self.0.send(payload)?;
         let value = SendFuture::new(JsFuture::from(promise)).await?;
-        // Miniflare's `send_email` binding resolves to `undefined`; real
-        // workerd resolves to `{ messageId }`. Tolerate both so local dev
-        // with `wrangler dev` doesn't throw on deserialize.
-        if value.is_undefined() || value.is_null() {
-            return Ok(EmailSendResult::default());
-        }
         Ok(serde_wasm_bindgen::from_value(value)?)
     }
 }
 
 /// Return value of a successful send.
-#[derive(Debug, Clone, Default, Deserialize)]
+#[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct EmailSendResult {
     /// The runtime-assigned message id (also exposed as the `Message-ID`
     /// header on the delivered message).
-    ///
-    /// Empty under `miniflare` (used by `wrangler dev`), which resolves the
-    /// binding with no value; real workerd populates it.
     pub message_id: String,
 }