diff --git a/src/notes/utils.spec.ts b/src/notes/utils.spec.ts
new file mode 100644
index 000000000..0666e55d1
--- /dev/null
+++ b/src/notes/utils.spec.ts
@@ -0,0 +1,22 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { randomBytes } from 'crypto';
+import { generatePublicId } from './utils';
+jest.mock('crypto');
+
+it('generatePublicId', () => {
+  const random128bitBuffer = Buffer.from([
+    0xe1, 0x75, 0x86, 0xb7, 0xc3, 0xfb, 0x03, 0xa9, 0x26, 0x9f, 0xc9, 0xd6,
+    0x8c, 0x2d, 0x7b, 0x7b,
+  ]);
+  const mockRandomBytes = randomBytes as jest.MockedFunction<
+    typeof randomBytes
+  >;
+  mockRandomBytes.mockImplementationOnce((_) => random128bitBuffer);
+
+  expect(generatePublicId()).toEqual('w5trddy3zc1tj9mzs7b8rbbvfc');
+});