Unit Testing

The last step of this tutorial is to add some unit tests to the ApiController.

A unit test file ends with the spec.ts extension and is usually placed next to the file it is testing.

Open the file api.controller.spec.ts and replace its content.

// std

// The `assert` module provides a simple set of assertion tests.

import { ok, strictEqual } from 'assert';

// 3p

import { createController, getHttpMethod, getPath, isHttpResponseOK } from '@foal/core';

import { Connection, createConnection } from 'typeorm';

// App

import { Todo } from '../entities';

import { ApiController } from './api.controller';

// Define a group of tests.

describe('ApiController', () => {

let controller: ApiController;

let connection: Connection;

// Create a connection to the database before running all the tests.

before(async () => {

// The connection uses the configuration defined in the file config/test.json.

// By default, the file has three connection options:

// "database": "./test_db.sqlite3" -> Use a different database for running the tests.

// "synchronize": true -> Auto create the database schema when the connection is established.

// "dropSchema": true -> Drop the schema when the connection is established (empty the database).

connection = await createConnection();

});

// Close the database connection after running all the tests whether they succeed or failed.

after(() => connection.close());

// Create or re-create the controller before each test.

beforeEach(() => controller = createController(ApiController));

// Define a nested group of tests.

describe('has a "getTodos" method that', () => {

// Define a unit test.

it('should handle requests at GET /.', () => {

// Throw an error and make the test fail if the http method of `getTodos` is not GET.

strictEqual(getHttpMethod(ApiController, 'getTodos'), 'GET');

// Throw an error and make the test fail if the path of `getTodos` is not /todos.

strictEqual(getPath(ApiController, 'getTodos'), '/todos');

});

// Define a unit test.

it('should return an HttpResponseOK.', async () => {

// Create fake todos.

const todo1 = new Todo();

todo1.text = 'Todo 1';

const todo2 = new Todo();

todo2.text = 'Todo 2';

// Save the todos.

await connection.manager.save([ todo1, todo2 ]);

const response = await controller.getTodos();

ok(isHttpResponseOK(response), 'response should be an instance of HttpResponseOK.');

const body = response.body;

ok(Array.isArray(body), 'The body of the response should be an array.');

strictEqual(body[0].text, 'Todo 1');

strictEqual(body[1].text, 'Todo 2');

});

});

});

As a controller method returns an HttpResponse object, it is really easy to test the status and body of the response.

If the controller method takes a Context object as argument, you can instantiate one like this: new Context({ /* content of the express request object */}).

Run the tests.

npm run test

This command watches at your tests and tested files in the app/ and scripts/ directories. When a file is modified, it automatically recompiles and re-runs your tests.

You should now end up with this output:

Congratulations! You have reached the end of this tutorial!

If you have any questions, feel free to open an issue on Github!

The entire source code is available here.