test: replace metadata sleeps with upstream start barriers (WealthLedger/backend#63) (#102)

test/tbank-operations-sync.e2e-spec.ts

@@ -151,8 +151,12 @@ describe('Request-driven operations synchronization (SQLite)', () => {
 
   it('joins overlapping account and instrument refresh into one atomic publication group', async () => {
     const gate = deferred<TbankOperationsByCursorResponse>();
+    const started = deferred<void>();
     upstream.getOperationsByCursor
-      .mockReturnValueOnce(gate.promise)
+      .mockImplementationOnce(() => {
+        started.resolve();
+        return gate.promise;
+      })
       .mockResolvedValue({
         hasNext: false,
         items: [{ ...operation(), instrumentUid: 'uid' }],
@@ -164,7 +168,7 @@ describe('Request-driven operations synchronization (SQLite)', () => {
         true,
       ),
     );
-    await delay(5);
+    await started.promise;
     const whole = requiredHandle(
       await service.request('owner', [january], true),
     );