Supertest setup (#24)

Setup supertest to test http endpoints. 

Split `index.ts` to `server.ts` with `listen` and `app.ts` with
endpoints. This is done, so testing of endpoints will be possible
without calling `listen` (that way supertest can assign its own port,
also no need to worry about closing down the server).

It turn out that imports of `ts` files need to end with `.js`, otherwise
they will not work after `tsc`. See `server.ts`

---------

Co-authored-by: Karol Wąsowski <wasowski02@protonmail.com>

.github/workflows/test.yml

@@ -36,8 +36,6 @@ jobs:
       - name: Start server
         run: |
           yarn install
-          yarn start &
-          sleep 10
           yarn test
       - name: Upload coverage reports to Codecov
         env:

package.json

@@ -7,7 +7,7 @@
   "type": "module",
   "license": "MIT",
   "scripts": {
-    "start": "tsc && node dist/index.js",
+    "start": "tsc && node dist/server.js",
     "build": "tsc",
     "test": "jest src/tests --coverage --config package.json",
     "lint": "eslint --ext '.js,.ts,.tsx' src/",
@@ -26,6 +26,7 @@
     "eslint-plugin-promise": "^6.0.0",
     "husky": "^8.0.0",
     "prettier": "2.8.4",
+    "supertest": "^6.3.3",
     "ts-jest": "^29.0.5",
     "typescript": "4.9.5"
   },
@@ -39,6 +40,7 @@
     "testEnvironment": "node",
     "collectCoverageFrom": [
       "src/*.ts"
-    ]
+    ],
+    "preset": "ts-jest"
   }
 }

src/app.ts

@@ -0,0 +1,8 @@
+import express from 'express'
+
+export const app = express()
+export const port = 42069
+
+app.get('/test', (req, res) => {
+  res.send('Hello from typescript express!')
+})

src/server.ts

@@ -0,0 +1,5 @@
+import { app, port } from './app.js'
+
+app.listen(port, () => {
+  console.log(`[server]: Server is running at localhost:${port}`)
+})

src/tests/app.test.ts

@@ -0,0 +1,12 @@
+import { app } from '../app'
+
+import request from 'supertest'
+
+test('Simple test', (done) => {
+  request(app)
+    .get('/test')
+    .expect(200)
+    .expect('Content-Type', 'text/html; charset=utf-8')
+    .expect('Hello from typescript express!')
+    .end(done)
+})