fix: fix CI-flaky database test timing

DatabaseEventBusStore: 500ms → 2000ms for the performance threshold
when cleaning 100k rows — this is intentionally a perf test so a real
time assertion is correct, it just needs more headroom for CI.

DatabaseKeyStore: replace fixed 500ms sleep with waitForExpect polling
so the test adapts to however long the async deletion actually takes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/backend-defaults/src/entrypoints/auth/plugin/keys/DatabaseKeyStore.test.ts

@@ -19,6 +19,7 @@ import {
   TestDatabases,
   mockServices,
 } from '@backstage/backend-test-utils';
+import waitForExpect from 'wait-for-expect';
 import { DatabaseKeyStore, TABLE } from './DatabaseKeyStore';
 
 const testKey = {
@@ -104,12 +105,13 @@ describe('DatabaseKeyStore', () => {
         "Removing expired plugin service keys, 'test-key-2'",
       );
 
-      // Key deletion happens async, so give it a bit of time to complete
-      await new Promise(resolve => setTimeout(resolve, 500));
-
-      await expect(knex(TABLE).select('id')).resolves.toEqual([
-        { id: testKey.kid },
-      ]);
+      // Key deletion happens async — poll until it completes rather than
+      // relying on a fixed sleep that can flake in slow CI environments.
+      await waitForExpect(async () => {
+        await expect(knex(TABLE).select('id')).resolves.toEqual([
+          { id: testKey.kid },
+        ]);
+      });
     });
 
     it('should fail to insert with invalid date', async () => {

plugins/events-backend/src/service/hub/DatabaseEventBusStore.test.ts

@@ -178,9 +178,9 @@ describe.each(databases.eachSupportedId())(
 
       await store.clean();
 
-      // Local testing shows this takes about 80ms, but if this is flaky we can
-      // reduce the count down to 10_000.
-      expect(Date.now() - start).toBeLessThan(500);
+      // Local testing shows this takes about 80ms, but CI containers can
+      // be significantly slower under load.
+      expect(Date.now() - start).toBeLessThan(2000);
 
       await expect(db('event_bus_events').count()).resolves.toEqual([
         { count: '5' },