feat: add test cases

Signed-off-by: SuZhou-Joe <[email protected]>

server/utils/csv-parser-helper.test.ts

@@ -0,0 +1,21 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { getJsonFromString } from './csv-parser-helper';
+
+describe('getJsonFromString', () => {
+  it('return correct answer', async () => {
+    expect(await getJsonFromString('title,id\n1,2')).toEqual([
+      {
+        title: '1',
+        id: '2',
+      },
+    ]);
+  });
+
+  it('return empty array when string is not in correct format', async () => {
+    expect(await getJsonFromString('1,2')).toEqual([]);
+  });
+});