diff --git a/src/helpers/reject-after.ts b/src/helpers/reject-after.ts
index 26cebc0..c6bcb1b 100644
--- a/src/helpers/reject-after.ts
+++ b/src/helpers/reject-after.ts
@@ -1,6 +1,10 @@
 import { setTimeout } from "node:timers/promises"
+import { toError } from "./to-error.js"
 
-export async function rejectAfter(timeMs: number) {
+export async function rejectAfter(
+  timeMs: number,
+  error: unknown = `rejected after ${timeMs}ms`,
+): Promise<never> {
   await setTimeout(timeMs)
-  return Promise.reject(`rejected after ${timeMs}ms`)
+  return Promise.reject(toError(error))
 }
diff --git a/src/helpers/wait-for-with-timeout.ts b/src/helpers/wait-for-with-timeout.ts
index 66f5319..6a93e85 100644
--- a/src/helpers/wait-for-with-timeout.ts
+++ b/src/helpers/wait-for-with-timeout.ts
@@ -5,6 +5,7 @@ import { waitFor } from "./wait-for.js"
 export function waitForWithTimeout(
   condition: () => MaybePromise<boolean>,
   timeout = 1000,
+  errorMessage = `timed out after ${timeout}ms`,
 ) {
-  return Promise.race([waitFor(condition), rejectAfter(timeout)])
+  return Promise.race([waitFor(condition), rejectAfter(timeout, errorMessage)])
 }