chore(structure): fix TU

src/structures/services/structures.service.spec.ts

@@ -39,7 +39,7 @@ const mockStructureModel = {
   deleteOne: jest.fn(),
   exec: jest.fn(),
   find: jest.fn(),
-  findById: jest.fn(),
+  findById: jest.fn().mockReturnThis(),
   findByIdAndUpdate: jest.fn(),
   findOne: jest.fn(),
   limit: jest.fn(),
@@ -515,14 +515,14 @@ describe('StructuresService', () => {
   describe('addPersonalOffer', () => {
     const personalOfferDocumentMock: PersonalOfferDocument = personalOffersDataMock[0] as PersonalOfferDocument;
     it('should add personal offer to the structure', async () => {
-      jest.spyOn(structureService, 'findOne').mockResolvedValue(structuresDocumentDataMock[0]);
+      mockStructureModel.exec.mockResolvedValue(structuresDocumentDataMock[0]);
       const expectedResult = { ...structuresDocumentDataMock[0], personalOffers: [personalOfferDocumentMock._id] };
       expect(await structureService.addPersonalOffer('6093ba0e2ab5775cfc01ed3e', personalOfferDocumentMock)).toEqual(
         expectedResult
       );
     });
     it('should return exception if structure is not found for given id', async () => {
-      jest.spyOn(structureService, 'findOne').mockResolvedValue(null);
+      mockStructureModel.exec.mockResolvedValue(null);
       try {
         await structureService.addPersonalOffer('abcd', personalOfferDocumentMock);
         expect(true).toBe(false);
@@ -532,7 +532,7 @@ describe('StructuresService', () => {
       }
     });
     it('should return exception if personal offer already exists in the structure', async () => {
-      jest.spyOn(structureService, 'findOne').mockResolvedValue(structuresDocumentDataMock[1]);
+      mockStructureModel.exec.mockResolvedValue(structuresDocumentDataMock[1]);
       try {
         await structureService.addPersonalOffer('6093ba0e2ab5775cfc01ed3e', personalOfferDocumentMock);
         expect(true).toBe(false);