test(backend): add a case for not finding a preprint

This change adds a test case for when a preprint cannot be found.

The test case is straightforward but requires changes to be able to support it. As there's a strong coupling between the code and the ORM (e.g. through `getFields`), we can't replace the repositories with in-memory versions. Worse, some of the code requires Postgres SQL, rather than the generic type we can use across different databases.

As a result, we have to try and use an actual Postgres instance. Doing so makes the tests slower and harder to develop. (Docker solves the problem for CI, but Jest tests should be isolated enough that they can be run locally, such as in the developer's IDE.)

To try and reduce the complexity, this uses pg-mem (https://github.com/oguimbal/pg-mem), an in-memory emulation of Postgres. I've not used this before, and the readme clearly labels it as experimental, but it's worked for what I've tried so far. It has a nice rollback feature, which allows resetting the database before each test. There's probably going to be pitfuls, but it seems to be worth continuing.

I had to change the codebase to allow passing in pg-mem's customised MikroORM. Unfortunately, there isn't a clean separation between the ORM and its database connection; I'd be much happier just passing in the latter to the app, but this will have to do for now.

Refs #388, #391, #419

package.json

@@ -185,6 +185,7 @@
     "nodemon": "^2.0.6",
     "npm-watch": "^0.9.0",
     "parcel": "2.0.0-beta.2",
+    "pg-mem": "^2.1.7",
     "prettier": "^2.4.1",
     "rimraf": "^3.0.2",
     "supertest": "^6.1.6",

src/backend/index.ts

@@ -1,5 +1,7 @@
+import { MikroORM } from '@mikro-orm/core';
 import { createServer } from 'http';
 import config from './config';
+import ormConfig from './mikro-orm.config';
 import configServer from './server';
 
 /**
@@ -12,7 +14,8 @@ async function bootstrap() {
    * await sequelize.authenticate()
    */
   config.parse(process.argv);
-  return createServer(await configServer(config)).listen(config.port);
+  const orm = await MikroORM.init(ormConfig);
+  return createServer(await configServer(orm, config)).listen(config.port);
 }
 
 bootstrap()

src/backend/scripts/dbInit.ts

@@ -1,9 +1,10 @@
-import { dbWrapper } from '../db';
+import { MikroORM } from '@mikro-orm/core';
+import dbConfig from '../mikro-orm.config';
 import { groupModelWrapper } from '../models';
 
 async function main() {
   try {
-    const [db] = await dbWrapper();
+    const db = await MikroORM.init(dbConfig);
     const groups = groupModelWrapper(db);
     const adminGroup = groups.create({ name: 'admins' });
     console.log('Created admins group:', adminGroup);

src/backend/server.ts

@@ -1,4 +1,5 @@
 // Node modules
+import { MikroORM, RequestContext } from '@mikro-orm/core';
 import { RequestListener } from 'http';
 import path from 'path';
 
@@ -25,7 +26,6 @@ import serialize from 'serialize-javascript';
 
 // Our modules
 import { createError } from './utils/http-errors';
-import { dbWrapper } from './db';
 
 // Our middlewares
 import authWrapper from './middleware/auth.js'; // authorization/user roles
@@ -88,6 +88,7 @@ const startTime = Symbol.for('request-received.startTime');
 type Config = Record<string, string>; // TODO add correct type
 
 export default async function configServer(
+  db: MikroORM,
   config: Config,
 ): Promise<RequestListener> {
   // Initialize our application server
@@ -113,8 +114,7 @@ export default async function configServer(
   server.use(xRequestId());
 
   // Initialize database
-  const [db, dbMiddleware] = await dbWrapper();
-  server.use(dbMiddleware);
+  server.use((_, next) => RequestContext.createAsync(db.em, next));
 
   // Setup auth handlers
   const userModel = userModelWrapper(db);

test/backend/preprints.test.ts

@@ -0,0 +1,19 @@
+import { StatusCodes } from 'http-status-codes';
+import request from 'supertest';
+import { createServer } from '../setup';
+
+describe('preprints', () => {
+  it('returns a 404 when not found', async () => {
+    const response = await request(await createServer()).get(
+      '/api/v2/preprints/doi-10.5555-12345678',
+    );
+
+    expect(response.status).toBe(StatusCodes.NOT_FOUND);
+    expect(response.type).toBe('application/json');
+    expect(response.body).toStrictEqual({
+      message: 'That preprint with ID doi-10.5555-12345678 does not exist.',
+      status: 'HTTP 404 Error.',
+      statusCode: 404,
+    });
+  });
+});

test/setup.ts

@@ -1,8 +1,31 @@
+import { MikroORM } from '@mikro-orm/core';
+import { PostgreSqlDriver } from '@mikro-orm/postgresql';
 import { RequestListener } from 'http';
+import { IBackup, newDb } from 'pg-mem';
+import dbConfig from '../src/backend/mikro-orm.config';
 import configServer from '../src/backend/server';
 
+let orm: MikroORM<PostgreSqlDriver>;
+let backup: IBackup;
+
+global.beforeAll(async () => {
+  const db = newDb();
+  orm = await db.adapters.createMikroOrm(dbConfig);
+  const generator = orm.getSchemaGenerator();
+
+  await generator.createSchema();
+
+  backup = db.backup();
+});
+
+global.afterAll(async () => {
+  await orm.close(true);
+});
+
 export async function createServer(config = {}): Promise<RequestListener> {
-  return await configServer({
+  backup.restore();
+
+  return await configServer(orm, {
     logLevel: 'off',
     orcidCallbackUrl: 'http://localhost/',
     orcidClientId: 'orcid-client-id',