fix(tbank): isolate caches by connection generation

src/tbank/brokerage-operations.service.spec.ts

@@ -1,5 +1,6 @@
 import {
   BadRequestException,
+  ConflictException,
   NotFoundException,
   ServiceUnavailableException,
 } from '@nestjs/common';
@@ -25,12 +26,14 @@ describe('BrokerageOperationsService', () => {
     metadata as never,
   );
   let operationsRequest: unknown;
+  let generation: string;
 
   beforeEach(() => {
     jest.clearAllMocks();
     access.withAccount.mockReset();
     tbank.getOperationsByCursor.mockReset();
     metadata.resolve.mockReset();
+    generation = 'generation-1';
     access.withAccount.mockImplementation(
       (
         _userId: string,
@@ -39,6 +42,7 @@ describe('BrokerageOperationsService', () => {
       ) =>
         handler({
           token: 'token',
+          generation,
           account: { id: 'account', type: 'ACCOUNT_TYPE_TINKOFF', name: '' },
         }),
     );
@@ -254,6 +258,54 @@ describe('BrokerageOperationsService', () => {
     expect(tbank.getOperationsByCursor).toHaveBeenCalledTimes(1);
   });
 
+  it('does not reuse a cached ledger page across connection generations', async () => {
+    const query = { from: '2025-01-01', to: '2025-01-31' };
+
+    await service.get('user', 'account', query);
+    await service.get('user', 'account', query);
+    generation = 'generation-2';
+    await service.get('user', 'account', query);
+
+    expect(tbank.getOperationsByCursor).toHaveBeenCalledTimes(2);
+  });
+
+  it('does not reuse a cached ledger page after the connection is deleted', async () => {
+    const query = { from: '2025-01-01', to: '2025-01-31' };
+    await service.get('user', 'account', query);
+    access.withAccount.mockRejectedValueOnce(
+      new ConflictException({ code: 'TBANK_NOT_CONNECTED' }),
+    );
+
+    await expect(service.get('user', 'account', query)).rejects.toEqual(
+      expect.any(ConflictException),
+    );
+    expect(tbank.getOperationsByCursor).toHaveBeenCalledTimes(1);
+  });
+
+  it('keeps a late previous-generation page unavailable to ledger and income collection', async () => {
+    let finishPrevious: ((value: unknown) => void) | undefined;
+    const previous = new Promise((resolve) => {
+      finishPrevious = resolve;
+    });
+    tbank.getOperationsByCursor
+      .mockReturnValueOnce(previous)
+      .mockResolvedValueOnce({
+        items: [operation('current')],
+      });
+    const range = { from: '2025-01-01', to: '2025-01-31' };
+
+    const previousRequest = service.collectRanges('user', 'account', [range]);
+    generation = 'generation-2';
+    const current = await service.collectRanges('user', 'account', [range]);
+    finishPrevious?.({ items: [operation('previous')] });
+    await previousRequest;
+    const reused = await service.collectRanges('user', 'account', [range]);
+
+    expect(current.pages[0][0].items[0].id).toBe('current');
+    expect(reused.pages[0][0].items[0].id).toBe('current');
+    expect(tbank.getOperationsByCursor).toHaveBeenCalledTimes(2);
+  });
+
   it('collects every cursor page and rejects a malformed continuation cursor', async () => {
     tbank.getOperationsByCursor
       .mockResolvedValueOnce({ hasNext: true, nextCursor: 'next', items: [] })
@@ -311,3 +363,11 @@ describe('BrokerageOperationsService', () => {
     expect(tbank.getOperationsByCursor).toHaveBeenCalledTimes(102);
   });
 });
+
+function operation(id: string) {
+  return {
+    id,
+    date: { seconds: '1' },
+    type: 'OPERATION_TYPE_COUPON',
+  };
+}