diff --git a/ts/test-node/helpers.ts b/ts/test-node/helpers.ts
deleted file mode 100644
index f24de9311a..0000000000
--- a/ts/test-node/helpers.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2020 Signal Messenger, LLC
-// SPDX-License-Identifier: AGPL-3.0-only
-
-import { assert } from 'chai';
-
-export async function assertRejects(fn: () => Promise<unknown>): Promise<void> {
-  let err: unknown;
-  try {
-    await fn();
-  } catch (e) {
-    err = e;
-  }
-  assert(
-    err instanceof Error,
-    'Expected promise to reject with an Error, but it resolved'
-  );
-}
diff --git a/ts/test-node/jobs/JobQueue_test.ts b/ts/test-node/jobs/JobQueue_test.ts
index 318aa3b1ec..34b028b317 100644
--- a/ts/test-node/jobs/JobQueue_test.ts
+++ b/ts/test-node/jobs/JobQueue_test.ts
@@ -13,7 +13,6 @@ import PQueue from 'p-queue';
 import { JobError } from '../../jobs/JobError';
 import { TestJobQueueStore } from './TestJobQueueStore';
 import { missingCaseError } from '../../util/missingCaseError';
-import { assertRejects } from '../helpers';
 import type { LoggerType } from '../../types/Logging';
 
 import { JobQueue } from '../../jobs/JobQueue';
@@ -803,8 +802,8 @@ describe('JobQueue', () => {
 
       noopQueue.streamJobs();
 
-      await assertRejects(() => noopQueue.streamJobs());
-      await assertRejects(() => noopQueue.streamJobs());
+      await assert.isRejected(noopQueue.streamJobs());
+      await assert.isRejected(noopQueue.streamJobs());
 
       sinon.assert.calledOnce(fakeStore.stream as sinon.SinonStub);
     });
@@ -834,7 +833,7 @@ describe('JobQueue', () => {
         maxAttempts: 99,
       });
 
-      await assertRejects(() => noopQueue.add(undefined));
+      await assert.isRejected(noopQueue.add(undefined));
 
       sinon.assert.notCalled(fakeStore.stream as sinon.SinonStub);
     });
diff --git a/ts/test-node/util/windowsZoneIdentifier_test.ts b/ts/test-node/util/windowsZoneIdentifier_test.ts
index 91ab1f9fed..7fa60bb8e3 100644
--- a/ts/test-node/util/windowsZoneIdentifier_test.ts
+++ b/ts/test-node/util/windowsZoneIdentifier_test.ts
@@ -1,4 +1,4 @@
-// Copyright 2020 Signal Messenger, LLC
+// Copyright 2020-2021 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import { assert } from 'chai';
@@ -7,7 +7,6 @@ import * as os from 'os';
 import * as fs from 'fs';
 import * as fse from 'fs-extra';
 import * as Sinon from 'sinon';
-import { assertRejects } from '../helpers';
 
 import { writeWindowsZoneIdentifier } from '../../util/windowsZoneIdentifier';
 
@@ -47,13 +46,13 @@ describe('writeWindowsZoneIdentifier', () => {
     await fse.outputFile(file, 'hello');
     await fs.promises.writeFile(`${file}:Zone.Identifier`, '# already here');
 
-    await assertRejects(() => writeWindowsZoneIdentifier(file));
+    await assert.isRejected(writeWindowsZoneIdentifier(file));
   });
 
   it('fails if the original file does not exist', async function thisNeeded() {
     const file = path.join(this.tmpdir, 'file-never-created.txt');
 
-    await assertRejects(() => writeWindowsZoneIdentifier(file));
+    await assert.isRejected(writeWindowsZoneIdentifier(file));
   });
 
   it('fails if not on Windows', async function thisNeeded() {
@@ -62,6 +61,6 @@ describe('writeWindowsZoneIdentifier', () => {
     const file = path.join(this.tmpdir, 'file.txt');
     await fse.outputFile(file, 'hello');
 
-    await assertRejects(() => writeWindowsZoneIdentifier(file));
+    await assert.isRejected(writeWindowsZoneIdentifier(file));
   });
 });