diff --git a/examples/async/src/server.ts b/examples/async/src/server.ts
index 174b1020..50030a69 100644
--- a/examples/async/src/server.ts
+++ b/examples/async/src/server.ts
@@ -5,11 +5,10 @@ import { tsonOptions } from "./shared.js";
 
 const tsonStringifyAsync = createTsonStringifyAsync(tsonOptions);
 
-const randomNumber = (min: number, max: number) => {
-	return Math.floor(Math.random() * (max - min + 1) + min);
-};
+const randomNumber = (min: number, max: number) =>
+	Math.floor(Math.random() * (max - min + 1) + min);
 
-const wait = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
+const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
 
 /**
  * This function returns the object we will be sending to the client.
@@ -18,7 +17,7 @@ export function getResponseShape() {
 	async function* bigintGenerator() {
 		const iterate = new Array(10).fill(0).map((_, i) => BigInt(i));
 		for (const number of iterate) {
-			await wait(randomNumber(1, 400));
+			await sleep(randomNumber(1, 400));
 			yield number;
 		}
 	}
@@ -26,7 +25,7 @@ export function getResponseShape() {
 	async function* numberGenerator() {
 		const iterate = new Array(10).fill(0).map((_, i) => i);
 		for (const number of iterate) {
-			await wait(randomNumber(1, 400));
+			await sleep(randomNumber(1, 400));
 			yield number;
 		}
 	}
diff --git a/src/async/deserializeAsync.test.ts b/src/async/deserializeAsync.test.ts
index ec907cfd..afd6f33b 100644
--- a/src/async/deserializeAsync.test.ts
+++ b/src/async/deserializeAsync.test.ts
@@ -27,7 +27,7 @@ test("deserialize variable chunk length", async () => {
 	});
 	{
 		const iterable = (async function* () {
-			await new Promise((resolve) => setTimeout(resolve, 1));
+			await sleep(1);
 			yield '[\n{"json":{"foo":"bar"},"nonce":"__tson"}';
 			yield "\n,\n[\n]\n]";
 		})();
@@ -37,7 +37,7 @@ test("deserialize variable chunk length", async () => {
 
 	{
 		const iterable = (async function* () {
-			await new Promise((resolve) => setTimeout(resolve, 1));
+			await sleep(1);
 			yield '[\n{"json":{"foo":"bar"},"nonce":"__tson"}\n,\n[\n]\n]';
 		})();
 		const result = await tson.parse(iterable);
@@ -46,7 +46,7 @@ test("deserialize variable chunk length", async () => {
 
 	{
 		const iterable = (async function* () {
-			await new Promise((resolve) => setTimeout(resolve, 1));
+			await sleep(1);
 			yield '[\n{"json"';
 			yield ':{"foo":"b';
 			yield 'ar"},"nonce":"__tson"}\n,\n';
@@ -100,13 +100,13 @@ test("stringify async iterable + promise", async () => {
 	});
 
 	async function* iterable() {
-		await new Promise((resolve) => setTimeout(resolve, 1));
+		await sleep(1);
 		yield 1n;
-		await new Promise((resolve) => setTimeout(resolve, 1));
+		await sleep(1);
 		yield 2n;
 		yield 3n;
 
-		await new Promise((resolve) => setTimeout(resolve, 2));
+		await sleep(1);
 		yield 4n;
 		yield 5n;
 	}
@@ -138,7 +138,7 @@ test("e2e: stringify async iterable and promise over the network", async () => {
 	function createMockObj() {
 		async function* generator() {
 			for (const number of [1n, 2n, 3n, 4n, 5n]) {
-				await new Promise((resolve) => setTimeout(resolve, 1));
+				await sleep(1);
 				yield number;
 			}
 		}
@@ -234,7 +234,7 @@ test("iterator error", async () => {
 			for (let index = 0; index < 3; index++) {
 				yield `item: ${index}`;
 
-				await new Promise((resolve) => setTimeout(resolve, 1));
+				await sleep(1);
 			}
 
 			// resolve the deferred after crash
diff --git a/src/async/handlers/tsonPromise.test.ts b/src/async/handlers/tsonPromise.test.ts
index 6539248d..af02d7b8 100644
--- a/src/async/handlers/tsonPromise.test.ts
+++ b/src/async/handlers/tsonPromise.test.ts
@@ -14,6 +14,7 @@ import {
 	sleep,
 	waitError,
 } from "../../internals/testUtils.js";
+import { createPromise } from "../../internals/testUtils.js";
 import { createTsonParseAsyncInner } from "../deserializeAsync.js";
 import {
 	mapIterable,
@@ -21,19 +22,6 @@ import {
 } from "../iterableUtils.js";
 import { TsonAsyncValueTuple } from "../serializeAsync.js";
 
-const createPromise = <T>(result: () => T, wait = 1) => {
-	return new Promise<T>((resolve, reject) => {
-		setTimeout(() => {
-			try {
-				const res = result();
-				resolve(res);
-			} catch (err) {
-				reject(err);
-			}
-		}, wait);
-	});
-};
-
 const tsonError: TsonType<
 	Error,
 	{
diff --git a/src/async/serializeAsync.test.ts b/src/async/serializeAsync.test.ts
index 48b77e93..aaa354f0 100644
--- a/src/async/serializeAsync.test.ts
+++ b/src/async/serializeAsync.test.ts
@@ -1,6 +1,7 @@
 import { expect, test } from "vitest";
 
 import { tsonAsyncIterator, tsonBigint, tsonPromise } from "../index.js";
+import { sleep } from "../internals/testUtils.js";
 import {
 	createAsyncTsonSerialize,
 	createTsonStringifyAsync,
@@ -106,9 +107,9 @@ test("serialize async iterable", async () => {
 	});
 
 	async function* iterable() {
-		await new Promise((resolve) => setTimeout(resolve, 1));
+		await sleep(1);
 		yield 42;
-		await new Promise((resolve) => setTimeout(resolve, 1));
+		await sleep(1);
 		yield 43;
 	}
 
@@ -163,7 +164,7 @@ test("stringify async iterable + promise", async () => {
 	});
 
 	async function* iterable() {
-		await new Promise((resolve) => setTimeout(resolve, 1));
+		await sleep(1);
 		yield 1n;
 		yield 2n;
 	}
diff --git a/src/internals/testUtils.ts b/src/internals/testUtils.ts
index 560a1b22..0183ff5d 100644
--- a/src/internals/testUtils.ts
+++ b/src/internals/testUtils.ts
@@ -36,8 +36,7 @@ export const waitFor = async (fn: () => unknown) => {
 			await fn();
 			return;
 		} catch {
-			// wait 5ms
-			await new Promise((resolve) => setTimeout(resolve, 5));
+			await sleep(5);
 		}
 	}
 };
@@ -90,3 +89,15 @@ export function createDeferred<T>() {
 
 export const sleep = (ms: number) =>
 	new Promise((resolve) => setTimeout(resolve, ms));
+export const createPromise = <T>(result: () => T, wait = 1) => {
+	return new Promise<T>((resolve, reject) => {
+		setTimeout(() => {
+			try {
+				const res = result();
+				resolve(res);
+			} catch (err) {
+				reject(err);
+			}
+		}, wait);
+	});
+};