Minor refinements & tuning to system structure

src/dolls/dolls.service.spec.ts

@@ -75,13 +75,6 @@ describe('DollsService', () => {
       const createDto = { name: 'New Doll' };
       const userId = 'user-1';
 
-      // Mock the transaction callback to return the doll
-      jest
-        .spyOn(prismaService, '$transaction')
-        .mockImplementation(async (callback) => {
-          return callback(prismaService);
-        });
-
       await service.create(userId, createDto);
 
       expect(prismaService.doll.create).toHaveBeenCalledWith({

src/dolls/dto/active-doll.dto.ts

@@ -0,0 +1,48 @@
+import {
+  IsString,
+  IsNotEmpty,
+  IsOptional,
+  ValidateNested,
+} from 'class-validator';
+import { Type } from 'class-transformer';
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { DollConfigurationDto } from './create-doll.dto';
+
+export class ActiveDollDto {
+  @ApiProperty({
+    description: 'Unique identifier of the doll',
+    example: '550e8400-e29b-41d4-a716-446655440000',
+  })
+  @IsString()
+  @IsNotEmpty()
+  id: string;
+
+  @ApiProperty({
+    description: 'Display name of the doll',
+    example: 'My First Doll',
+  })
+  @IsString()
+  @IsNotEmpty()
+  name: string;
+
+  @ApiPropertyOptional({
+    description: 'Configuration for the doll',
+    type: DollConfigurationDto,
+  })
+  @IsOptional()
+  @ValidateNested()
+  @Type(() => DollConfigurationDto)
+  configuration?: DollConfigurationDto;
+
+  @ApiProperty({
+    description: 'Creation date of the doll',
+    example: '2023-01-01T00:00:00.000Z',
+  })
+  createdAt: Date;
+
+  @ApiProperty({
+    description: 'Last update date of the doll',
+    example: '2023-01-01T00:00:00.000Z',
+  })
+  updatedAt: Date;
+}