fix(backend): isolate health service unit test

apps/backend/src/modules/health/health.service.spec.ts

@@ -1,27 +1,43 @@
 import { Test, TestingModule } from '@nestjs/testing';
-import { ConfigModule } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import { HealthService } from './health.service';
 import { PrismaService } from '../prisma/prisma.service';
-import configuration from '../../config/configuration';
 
 describe('HealthService', () => {
   let service: HealthService;
   const prisma = { $queryRaw: vi.fn() } as any;
+  const config = {
+    get: vi.fn((key: string, fallback?: unknown) => {
+      const values: Record<string, unknown> = {
+        'app.moex.baseUrl': 'https://iss.moex.test/iss',
+        'app.tbank.token': 'token-1',
+      };
+
+      return values[key] ?? fallback;
+    }),
+  } as unknown as ConfigService;
+  const fetchMock = vi.fn();
 
   beforeEach(async () => {
     vi.clearAllMocks();
+    vi.stubGlobal('fetch', fetchMock);
+    fetchMock.mockResolvedValue({ ok: true, status: 200 });
 
     const module: TestingModule = await Test.createTestingModule({
-      imports: [ConfigModule.forRoot({ load: [configuration], isGlobal: true })],
       providers: [
         HealthService,
         { provide: PrismaService, useValue: prisma },
+        { provide: ConfigService, useValue: config },
       ],
     }).compile();
 
     service = module.get<HealthService>(HealthService);
   });
 
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
   it('returns ok when all dependencies are healthy', async () => {
     prisma.$queryRaw.mockResolvedValue([{ 1: 1 }]);