get project by id use case

src/repositories/in-memory-db/inMemoryProjectRepository.ts

@@ -32,4 +32,12 @@ export class InMemoryProjectRepository implements ProjectRepository {
 
     return projects
   }
+
+  async fetchProjectById(projectId: string): Promise<Project | null> {
+    const project = this.dbProject.find((project) => project.id === projectId)
+    if (!project) {
+      return null
+    }
+    return project
+  }
 }

src/repositories/prisma/prisma-project-repository.ts

@@ -21,4 +21,7 @@ export class PrismaProjectRepository implements ProjectRepository {
     return projects
   }
 
+  async fetchProjectById(_projectId: string): Promise<Project | null> {
+    throw new Error('Method not implemented.')
+  }
 }

src/repositories/project-repository.ts

@@ -3,4 +3,5 @@ import { Prisma, Project } from '@prisma/client'
 export interface ProjectRepository {
   create(data: Prisma.ProjectUncheckedCreateInput): Promise<Project>
   fetchProjectsByUserId(userId: string): Promise<Project[]>
+  fetchProjectById(projectId: string): Promise<Project | null>
 }

src/use-cases/getProjectsByIdUseCase.spec.ts

@@ -0,0 +1,45 @@
+import { expect, describe, it, beforeEach } from 'vitest'
+
+import { InMemoryProjectRepository } from '../repositories/in-memory-db/inMemoryProjectRepository'
+import { ProjectRepository } from '../repositories/project-repository'
+import { ResourceNotFoundError } from './errors/ResourceNotFoundError'
+import { GetProjectsByIdUseCase } from './getProjectsByIdUseCase'
+
+let projectRepository: ProjectRepository
+let getProjectByIdUseCase: GetProjectsByIdUseCase
+
+describe('Get Project By Id Use Case', () => {
+  beforeEach(() => {
+    projectRepository = new InMemoryProjectRepository()
+    getProjectByIdUseCase = new GetProjectsByIdUseCase(projectRepository)
+  })
+
+  it('should be able get project by ID', async () => {
+    const newProject = await projectRepository.create({
+      title: 'React Typescript 1',
+      description: 'Best Project',
+      tags: 'React',
+      link: 'https://github.com/luiseduardo3/nodets-petcanil',
+      user_id: 'user_id',
+    })
+
+    const { project } = await getProjectByIdUseCase.execute({
+      projectId: newProject.id,
+    })
+
+    expect(project).toEqual(
+      expect.objectContaining({
+        title: 'React Typescript 1',
+        id: newProject.id,
+      }),
+    )
+  })
+
+  it('should not be able to get a project that does not exist', async () => {
+    await expect(() =>
+      getProjectByIdUseCase.execute({
+        projectId: 'projectDoesNotExist',
+      }),
+    ).rejects.toBeInstanceOf(ResourceNotFoundError)
+  })
+})

src/use-cases/getProjectsByIdUseCase.ts

@@ -0,0 +1,31 @@
+import { Project } from '@prisma/client'
+
+import { ProjectRepository } from '../repositories/project-repository'
+
+import { ResourceNotFoundError } from './errors/ResourceNotFoundError'
+
+interface GetProjectByIdRequest {
+  projectId: string
+}
+
+interface GetProjectByIdResponse {
+  project: Project
+}
+
+export class GetProjectsByIdUseCase {
+  constructor(private projectRepository: ProjectRepository) {}
+
+  async execute({
+    projectId,
+  }: GetProjectByIdRequest): Promise<GetProjectByIdResponse> {
+    const project = await this.projectRepository.fetchProjectById(projectId)
+
+    if (!project) {
+      throw new ResourceNotFoundError()
+    }
+
+    return {
+      project,
+    }
+  }
+}