diff --git a/dbal/ts/tests/core/validation/validate-credential-create.test.ts b/dbal/ts/tests/core/validation/validate-credential-create.test.ts
new file mode 100644
index 000000000..2e576a0b5
--- /dev/null
+++ b/dbal/ts/tests/core/validation/validate-credential-create.test.ts
@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest'
+import { validateCredentialCreate } from '../../../src/core/validation/validate-credential-create'
+
+describe('validateCredentialCreate', () => {
+  const base = {
+    username: 'valid_user',
+    passwordHash: 'hashed_value',
+    firstLogin: true,
+  }
+
+  it.each([
+    { data: base, expected: [] },
+  ])('returns $expected for valid case', ({ data, expected }) => {
+    expect(validateCredentialCreate(data)).toEqual(expected)
+  })
+
+  it.each([
+    { data: { ...base, username: 'ab' }, message: 'username must be 3-50 characters (alphanumeric, underscore, hyphen)' },
+    { data: { ...base, passwordHash: ' ' }, message: 'passwordHash must be a non-empty string' },
+    { data: { ...base, firstLogin: 'yes' as unknown as boolean }, message: 'firstLogin must be a boolean' },
+  ])('rejects invalid case', ({ data, message }) => {
+    expect(validateCredentialCreate(data)).toContain(message)
+  })
+})
diff --git a/frontends/nextjs/src/lib/auth/auth.ts b/frontends/nextjs/src/lib/auth/auth.ts
index b041b4ad2..57b554ae2 100644
--- a/frontends/nextjs/src/lib/auth/auth.ts
+++ b/frontends/nextjs/src/lib/auth/auth.ts
@@ -9,5 +9,5 @@ export {
   getScrambledPassword,
   DEFAULT_USERS,
   DEFAULT_CREDENTIALS,
-} from './auth/index'
+} from './index'