feat: add basic unit tests for tracker ms

apps/tracker/src/stats/stats.service.spec.ts

@@ -1,25 +1,60 @@
 import { Test, TestingModule } from '@nestjs/testing';
 import { StatsService } from './stats.service';
-import { PrismaService } from '@reduced.to/prisma';
+import { PrismaService, Prisma } from '@reduced.to/prisma';
 
 describe('StatsService', () => {
   let service: StatsService;
+  let prismaService: PrismaService;
+
+  const mockPrismaService = {
+    visit: {
+      create: jest.fn(),
+      findFirst: jest.fn(),
+    },
+  };
+
 
   beforeEach(async () => {
     const module: TestingModule = await Test.createTestingModule({
       providers: [
         StatsService,
         {
           provide: PrismaService,
-          useValue: jest.fn(),
+          useValue: mockPrismaService
         },
       ],
     }).compile();
 
     service = module.get<StatsService>(StatsService);
+    prismaService = module.get<PrismaService>(PrismaService);
   });
 
   it('should be defined', () => {
     expect(service).toBeDefined();
   });
+
+  describe('addVisit', () => {
+    it('should handle PrismaClientKnownRequestError', async () => {
+      const error = new Prisma.PrismaClientKnownRequestError('message', {code: 'P2025', meta: {}, clientVersion: 'v1'});
+      mockPrismaService.visit.create.mockRejectedValue(error);
+      await expect(service.addVisit('testKey', { hashedIp: 'testIp', ua: 'testAgent' })).resolves.toBeUndefined();
+    });
+
+    it('should throw an error for unexpected errors', async () => {
+      mockPrismaService.visit.create.mockRejectedValue(new Error('Unexpected error'));
+      await expect(service.addVisit('testKey', { hashedIp: 'testIp', ua: 'testAgent' })).rejects.toThrow('Unexpected error');
+    });
+  });
+
+  describe('isUniqueVisit', () => {
+    it('should return true for a unique visit', async () => {
+      mockPrismaService.visit.findFirst.mockResolvedValue(null);
+      await expect(service.isUniqueVisit('testKey', 'testIp')).resolves.toBeTruthy();
+    });
+
+    it('should return false for a non-unique visit', async () => {
+      mockPrismaService.visit.findFirst.mockResolvedValue({ id: 1 });
+      await expect(service.isUniqueVisit('testKey', 'testIp')).resolves.toBeFalsy();
+    });
+  });
 });

apps/tracker/src/stats/stats.service.ts

@@ -27,9 +27,9 @@ export class StatsService {
           // Link record does not exist for the given key (might be a visit to a temporary link)
           return;
         }
-
-        throw err;
       }
+
+      throw err;
     }
   }