✨ feat: add GET /tasks/:id route

See https://stackoverflow.com/a/11760249 why we return 404 when ID not matching any task (instead of 200 or 202 or 204)

src/domain/entities/TaskRepository.ts

@@ -5,4 +5,6 @@ export interface TaskRepository {
   findAll(): Promise<TaskList>;
 
   save(task: Task): Promise<Task>;
+
+  findById(id: number): Promise<Task|null>;
 }

src/domain/usecases/queries/get_task_by_id.ts

@@ -0,0 +1,10 @@
+import { TaskRepository } from '../../entities/TaskRepository';
+import { Task } from '../../entities/Task';
+
+async function getTaskById(id: number, taskRepository: TaskRepository): Promise<Task | null> {
+  return await taskRepository.findById(id);
+}
+
+export {
+  getTaskById
+};

src/infrastructure/app.ts

@@ -1,8 +1,9 @@
-import fastify, { FastifyInstance } from 'fastify';
+import fastify, { FastifyInstance, FastifyReply, FastifyRequest } from 'fastify';
 import { listTasks } from '../domain/usecases/queries/list_tasks';
 import { createTask } from '../domain/usecases/commands/create_task';
 import { TaskRepository } from '../domain/entities/TaskRepository';
 import { container } from './container';
+import { getTaskById } from '../domain/usecases/queries/get_task_by_id';
 
 function build(): FastifyInstance {
   const logger = container.resolve('logger');
@@ -29,8 +30,19 @@ function build(): FastifyInstance {
   });
 
   // Get a task
-  server.get('/tasks/:id', async function (request, reply) {
-    reply.code(501).send();
+  server.get('/tasks/:id', async function (request: FastifyRequest<any>, reply: FastifyReply<any>) {
+    const taskId = parseInt(request.params.id);
+    if (isNaN(taskId)) {
+      reply.code(429).send();
+    } else {
+      const taskRepository: TaskRepository = container.resolve('taskRepository');
+      const task = await getTaskById(taskId, taskRepository);
+      if (!task) {
+        reply.code(404).send();
+      } else {
+        return task;
+      }
+    }
   });
 
   // Update a task

src/infrastructure/repositories/TaskRepositorySql.ts

@@ -54,4 +54,23 @@ export class TaskRepositorySql implements TaskRepository {
     }
     return domainTask;
   }
+
+  async findById(id: number): Promise<Task | null> {
+    const prisma = this.prisma;
+    try {
+      const prismaTask = await prisma.task.findUnique({ where: { id } });
+      if (prismaTask) {
+        return new Task({
+          id: prismaTask.id,
+          content: prismaTask.content,
+          createdAt: prismaTask.createdAt,
+          updatedAt: prismaTask.updatedAt,
+          status: prismaTask.status as Status
+        });
+      }
+    } finally {
+      await prisma.$disconnect();
+    }
+    return null;
+  }
 }

test/domain/usecases/commands/create_task.test.ts

@@ -11,6 +11,9 @@ describe('domain.usecases.commands.create_task', function () {
     const stubbedSavedTask: Task = new Task({ id: 1, createdAt: now, content: params.content });
 
     const taskRepository: TaskRepository = {
+      async findById(id: number): Promise<Task | null> {
+        return null;
+      },
       async findAll(): Promise<TaskList> {
         return new TaskList();
       },

test/domain/usecases/queries/list_tasks.test.ts

@@ -12,6 +12,9 @@ describe('domain.usecases.queries.list_tasks', function () {
     const taskList: TaskList = new TaskList([task1, task2]);
 
     const taskRepository: TaskRepository = {
+      async findById(id: number): Promise<Task | null> {
+        return null;
+      },
       async save(task: Task): Promise<Task> {
         return task;
       },

test/infrastructure/app.test.ts

@@ -22,7 +22,7 @@ describe('API', () => {
     });
 
     describe('GET /', () => {
-      it('should returns the list of all stored Tasks', async () => {
+      it('should return the list of all stored Tasks', async () => {
         // given
         const prisma = getPrismaClient();
         await prisma.task.createMany({
@@ -92,5 +92,52 @@ describe('API', () => {
         expect(json.updatedAt).toBeDefined();
       });
     });
+
+    describe('GET /:id', () => {
+      it('should return 200 with the task matching the given ID', async () => {
+        // given
+        const prisma = getPrismaClient();
+        await prisma.task.create({
+          data: {
+            id: 1,
+            content: 'Task 1 content',
+            status: 'DONE',
+            createdAt: new Date('2021-11-09T17:08:02.865Z'),
+            updatedAt: new Date('2021-11-09T17:08:02.866Z')
+          }
+        });
+
+        // when
+        const response = await server.inject({ method: 'GET', url: '/tasks/1' });
+
+        // then
+        expect(response.statusCode).toBe(200);
+        expect(response.json()).toStrictEqual({
+          content: 'Task 1 content',
+          createdAt: '2021-11-09T17:08:02.865Z',
+          id: 1,
+          status: 'DONE',
+          updatedAt: '2021-11-09T17:08:02.866Z'
+        });
+      });
+
+      it('should return 404 when no task ID matches the given ID', async () => {
+        // when
+        const response = await server.inject({ method: 'GET', url: '/tasks/999999' });
+
+        // then
+        expect(response.statusCode).toBe(404);
+      });
+
+      it('should return 429 when the given ID is not a number', async () => {
+        // given
+
+        // when
+        const response = await server.inject({ method: 'GET', url: '/tasks/bad_id' });
+
+        // then
+        expect(response.statusCode).toBe(429);
+      });
+    });
   });
 });