chore: strengthen backend eslint profile

src/integrations/ncr/ncr-ratings.client.spec.ts

@@ -1,4 +1,5 @@
 import { ServiceUnavailableException } from '@nestjs/common';
+
 import { NcrRatingsClient } from './ncr-ratings.client';
 const isin = 'RU000A10EW44';
 const row = (value = 'AAA.ru', code = isin, href = '/ratings/issues/123/') =>
@@ -65,6 +66,18 @@ describe('public NCR issue ratings', () => {
       );
     },
   );
+  it.each(['AA+.ru', 'B-.ru', 'BBB+.ru', 'CCC-.ru', 'CC.ru', 'D.ru'])(
+    'accepts the public rating grammar: %s', async (value) => {
+      jest.spyOn(global, 'fetch').mockResolvedValue(response(table(row(value))));
+      expect(await new NcrRatingsClient().rating(isin)).toMatchObject({ value });
+    },
+  );
+  it.each(['AAA+.ru', 'CC-.ru', 'BBBB.ru', 'BBB++.ru'])(
+    'rejects invalid rating grades: %s', async (value) => {
+      jest.spyOn(global, 'fetch').mockResolvedValue(response(table(row(value))));
+      await expect(new NcrRatingsClient().rating(isin)).rejects.toBeInstanceOf(ServiceUnavailableException);
+    },
+  );
   it('bounds outage retries then recovers without retaining a false missing rating', async () => {
     const fetchMock = jest
       .spyOn(global, 'fetch')