diff --git a/BackEnd/src/modules/quests/quests.service.spec.ts b/BackEnd/src/modules/quests/quests.service.spec.ts
new file mode 100644
index 00000000..9e05f8a7
--- /dev/null
+++ b/BackEnd/src/modules/quests/quests.service.spec.ts
@@ -0,0 +1,191 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { getRepositoryToken } from '@nestjs/typeorm';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { BadRequestException, ForbiddenException, NotFoundException } from '@nestjs/common';
+import { QuestsService } from './quests.service';
+import { Quest } from './entities/quest.entity';
+import { CacheService } from '../cache/cache.service';
+import { ModerationService } from '../moderation/moderation.service';
+
+const mockScan = { shouldBlock: false, keywordHits: [] };
+
+const mockRepo = () => ({
+  create: jest.fn(),
+  save: jest.fn(),
+  findOne: jest.fn(),
+  softDelete: jest.fn(),
+  createQueryBuilder: jest.fn(),
+});
+
+const mockCache = () => ({
+  get: jest.fn().mockResolvedValue(null),
+  set: jest.fn().mockResolvedValue(undefined),
+  delete: jest.fn().mockResolvedValue(undefined),
+  deletePattern: jest.fn().mockResolvedValue(undefined),
+});
+
+const mockModeration = () => ({
+  scanText: jest.fn().mockResolvedValue(mockScan),
+  saveQuestModerationItem: jest.fn().mockResolvedValue(undefined),
+});
+
+describe('QuestsService', () => {
+  let service: QuestsService;
+  let repo: ReturnType<typeof mockRepo>;
+  let cache: ReturnType<typeof mockCache>;
+  let moderation: ReturnType<typeof mockModeration>;
+  let emitter: { emit: jest.Mock };
+
+  beforeEach(async () => {
+    repo = mockRepo();
+    cache = mockCache();
+    moderation = mockModeration();
+    emitter = { emit: jest.fn() };
+
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        QuestsService,
+        { provide: getRepositoryToken(Quest), useValue: repo },
+        { provide: CacheService, useValue: cache },
+        { provide: EventEmitter2, useValue: emitter },
+        { provide: ModerationService, useValue: moderation },
+      ],
+    }).compile();
+
+    service = module.get<QuestsService>(QuestsService);
+  });
+
+  afterEach(() => jest.clearAllMocks());
+
+  // ─── create ──────────────────────────────────────────────────────────────
+
+  describe('create', () => {
+    const dto = { title: 'Test Quest', description: 'desc', rewardAmount: 10 };
+    const creator = 'GABC123';
+
+    it('saves and returns a quest', async () => {
+      const entity = { id: 'q1', ...dto, createdBy: creator, rewardAmount: 10 };
+      repo.create.mockReturnValue(entity);
+      repo.save.mockResolvedValue(entity);
+      jest.spyOn(require('./dto'), 'QuestResponseDto' as any, 'get').mockReturnValue({ fromEntity: (e: any) => e }).mockRestore?.();
+
+      // patch static method via prototype
+      const { QuestResponseDto } = require('./dto');
+      const spy = jest.spyOn(QuestResponseDto, 'fromEntity').mockReturnValue(entity as any);
+
+      const result = await service.create(dto as any, creator);
+      expect(repo.save).toHaveBeenCalledTimes(1);
+      expect(emitter.emit).toHaveBeenCalledWith('quest.created', expect.anything());
+      expect(cache.deletePattern).toHaveBeenCalled();
+      spy.mockRestore();
+    });
+
+    it('throws BadRequestException when end date is before start date', async () => {
+      const bad = {
+        ...dto,
+        startDate: new Date('2025-06-01'),
+        endDate: new Date('2025-05-01'),
+      };
+      await expect(service.create(bad as any, creator)).rejects.toThrow(BadRequestException);
+    });
+
+    it('throws BadRequestException when moderation blocks content', async () => {
+      moderation.scanText.mockResolvedValue({ shouldBlock: true, keywordHits: ['spam'] });
+      repo.create.mockReturnValue({ id: 'q1', ...dto, createdBy: creator });
+      repo.save.mockResolvedValue({ id: 'q1', ...dto, createdBy: creator });
+      await expect(service.create(dto as any, creator)).rejects.toThrow(BadRequestException);
+    });
+  });
+
+  // ─── findOne ─────────────────────────────────────────────────────────────
+
+  describe('findOne', () => {
+    it('returns cached value when available', async () => {
+      const cached = { id: 'q1', title: 'cached' };
+      cache.get.mockResolvedValue(cached);
+      const result = await service.findOne('q1');
+      expect(result).toEqual(cached);
+      expect(repo.findOne).not.toHaveBeenCalled();
+    });
+
+    it('throws NotFoundException when quest does not exist', async () => {
+      repo.findOne.mockResolvedValue(null);
+      await expect(service.findOne('missing')).rejects.toThrow(NotFoundException);
+    });
+  });
+
+  // ─── update ──────────────────────────────────────────────────────────────
+
+  describe('update', () => {
+    const existing = {
+      id: 'q1',
+      title: 'Old',
+      description: 'old desc',
+      createdBy: 'GABC',
+      status: 'DRAFT',
+      rewardAmount: 5,
+    };
+
+    it('throws NotFoundException when quest does not exist', async () => {
+      repo.findOne.mockResolvedValue(null);
+      await expect(service.update('q1', {}, 'GABC')).rejects.toThrow(NotFoundException);
+    });
+
+    it('throws ForbiddenException when caller is not the creator', async () => {
+      repo.findOne.mockResolvedValue(existing);
+      await expect(service.update('q1', {}, 'OTHER')).rejects.toThrow(ForbiddenException);
+    });
+
+    it('throws BadRequestException on invalid status transition', async () => {
+      repo.findOne.mockResolvedValue({ ...existing, status: 'COMPLETED' });
+      await expect(
+        service.update('q1', { status: 'DRAFT' } as any, 'GABC'),
+      ).rejects.toThrow(BadRequestException);
+    });
+  });
+
+  // ─── remove ──────────────────────────────────────────────────────────────
+
+  describe('remove', () => {
+    it('throws NotFoundException when quest does not exist', async () => {
+      repo.findOne.mockResolvedValue(null);
+      await expect(service.remove('q1', 'GABC')).rejects.toThrow(NotFoundException);
+    });
+
+    it('throws ForbiddenException when caller is not the creator', async () => {
+      repo.findOne.mockResolvedValue({ id: 'q1', createdBy: 'GABC' });
+      await expect(service.remove('q1', 'OTHER')).rejects.toThrow(ForbiddenException);
+    });
+
+    it('soft-deletes and emits event', async () => {
+      const entity = { id: 'q1', createdBy: 'GABC' };
+      repo.findOne.mockResolvedValue(entity);
+      repo.softDelete.mockResolvedValue(undefined);
+      await service.remove('q1', 'GABC');
+      expect(repo.softDelete).toHaveBeenCalledWith('q1');
+      expect(emitter.emit).toHaveBeenCalledWith('quest.deleted', expect.anything());
+    });
+  });
+
+  // ─── validateStatusTransition ────────────────────────────────────────────
+
+  describe('validateStatusTransition', () => {
+    it.each([
+      ['DRAFT', 'ACTIVE'],
+      ['DRAFT', 'ARCHIVED'],
+      ['ACTIVE', 'COMPLETED'],
+      ['ACTIVE', 'ARCHIVED'],
+      ['COMPLETED', 'ARCHIVED'],
+    ])('allows %s -> %s', (from, to) => {
+      expect(() => service.validateStatusTransition(from, to)).not.toThrow();
+    });
+
+    it.each([
+      ['ARCHIVED', 'ACTIVE'],
+      ['COMPLETED', 'DRAFT'],
+      ['ACTIVE', 'DRAFT'],
+    ])('rejects %s -> %s', (from, to) => {
+      expect(() => service.validateStatusTransition(from, to)).toThrow(BadRequestException);
+    });
+  });
+});
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