Writing tests

The best way to test an application is by writing tests that make sure it behaves to clients as we would expect. Feathers makes testing your application a lot easier because the services we create can be tested directly instead of having to fake HTTP requests and responses. In this chapter we will implement unit tests for our users and messages services.

You can run code linting and Mocha tests with:

npm test

This should already pass but it won't be testing any of the functionality we added in the guide so far.

Test database setup

When testing database functionality, we want to make sure that the tests use a different database. We can achieve this by updating the test environment configuration in config/test.json with the following content:

{
  "nedb": "../test/data"
}

This will set up the NeDB database to use test/data as the base directory instead of data/ when the NODE_ENV environment variable is set to test. The same thing can be done with connection strings for other databases.

Note: When using Git for version control, the data/ and test/data folders should be added to .gitignore.

We also want to make sure that the database is cleaned up before every test run. To make that possible across platforms, first run:

npm install shx --save-dev

Now we can update the scripts section of our package.json to the following:

  "scripts": {
    "test": "npm run eslint && npm run mocha",
    "eslint": "eslint src/. test/. --config .eslintrc.json",
    "start": "node src/",
    "clean": "shx rm -rf test/data/",
    "mocha": "npm run clean && NODE_ENV=test mocha test/ --recursive --exit"
  }

  "scripts": {
    "test": "npm run compile && npm run mocha",
    "dev": "ts-node-dev --no-notify src/",
    "start": "npm run compile && node lib/",
    "clean": "shx rm -rf test/data/",
    "mocha": "npm run clean && NODE_ENV=test ts-mocha \"test/**/*.ts\" --recursive --exit",
    "compile": "shx rm -rf lib/ && tsc"
  },

On Windows the mocha command should look like this:

npm run clean & SET NODE_ENV=test& mocha test/ --recursive --exit

This will make sure that the test/data folder is removed before every test run and NODE_ENV is set properly.

Testing services

To test the messages and users services (with all hooks wired up), we could use any REST API testing tool to make requests and verify that they return correct responses.

But there is a much faster, easier and complete approach. Since everything on top of our own hooks and services is already provided (and tested) by Feathers, we can require the application object and use the service methods directly. We "fake" authentication by setting params.user manually.

By default, the generator creates a service test file that only tests that the service exists.

E.g. like this in test/services/users.test.js:

const assert = require('assert');
const app = require('../../src/app');

describe('\'users\' service', () => {
  it('registered the service', () => {
    const service = app.service('users');

    assert.ok(service, 'Registered the service');
  });
});

E.g. like this in test/services/users.test.ts:

import assert from 'assert';
import app from '../../src/app';

describe('\'users\' service', () => {
  it('registered the service', () => {
    const service = app.service('users');

    assert.ok(service, 'Registered the service');
  });
});

We can then add similar tests that use the service. The first test below verifies that users can be created, the profile image gets set and the password gets encrypted. The second verifies that the password does not get sent to external requests:

Replace test/services/users.test.js with the following:

const assert = require('assert');
const app = require('../../src/app');

describe('\'users\' service', () => {
  it('registered the service', () => {
    const service = app.service('users');

    assert.ok(service, 'Registered the service');
  });

  it('creates a user, encrypts password and adds gravatar', async () => {
    const user = await app.service('users').create({
      email: 'test@example.com',
      password: 'secret'
    });

    // Verify Gravatar has been set as we'd expect
    assert.equal(user.avatar, 'https://s.gravatar.com/avatar/55502f40dc8b7c769880b10874abc9d0?s=60');
    // Makes sure the password got encrypted
    assert.ok(user.password !== 'secret');
  });

  it('removes password for external requests', async () => {
    // Setting `provider` indicates an external request
    const params = { provider: 'rest' };

    const user = await app.service('users').create({
      email: 'test2@example.com',
      password: 'secret'
    }, params);

    // Make sure password has been removed
    assert.ok(!user.password);
  });
});

Replace test/services/users.test.ts with the following:

import assert from 'assert';
import app from '../../src/app';

describe('\'users\' service', () => {
  it('registered the service', () => {
    const service = app.service('users');

    assert.ok(service, 'Registered the service');
  });

  it('creates a user, encrypts password and adds gravatar', async () => {
    const user = await app.service('users').create({
      email: 'test@example.com',
      password: 'secret'
    });

    // Verify Gravatar has been set as we'd expect
    assert.equal(user.avatar, 'https://s.gravatar.com/avatar/55502f40dc8b7c769880b10874abc9d0?s=60');
    // Makes sure the password got encrypted
    assert.ok(user.password !== 'secret');
  });

  it('removes password for external requests', async () => {
    // Setting `provider` indicates an external request
    const params = { provider: 'rest' };

    const user = await app.service('users').create({
      email: 'test2@example.com',
      password: 'secret'
    }, params);

    // Make sure password has been removed
    assert.ok(!user.password);
  });
});

We take a similar approach for the messages service test. We create a test-specific user from the users service, then pass it as params.user when creating a new message and validates that message's content:

Update test/services/messages.test.js as follows:

const assert = require('assert');
const app = require('../../src/app');

describe('\'messages\' service', () => {
  it('registered the service', () => {
    const service = app.service('messages');

    assert.ok(service, 'Registered the service');
  });

  it('creates and processes message, adds user information', async () => {
    // Create a new user we can use for testing
    const user = await app.service('users').create({
      email: 'messagetest@example.com',
      password: 'supersecret'
    });

    // The messages service call params (with the user we just created)
    const params = { user };
    const message = await app.service('messages').create({
      text: 'a test',
      additional: 'should be removed'
    }, params);

    assert.equal(message.text, 'a test');
    // `userId` should be set to passed users it
    assert.equal(message.userId, user._id);
    // Additional property has been removed
    assert.ok(!message.additional);
    // `user` has been populated
    assert.deepEqual(message.user, user);
  });
});

Update test/services/messages.test.ts as follows:

import assert from 'assert';
import app from '../../src/app';

describe('\'messages\' service', () => {
  it('registered the service', () => {
    const service = app.service('messages');

    assert.ok(service, 'Registered the service');
  });

  it('creates and processes message, adds user information', async () => {
    // Create a new user we can use for testing
    const user = await app.service('users').create({
      email: 'messagetest@example.com',
      password: 'supersecret'
    });

    // The messages service call params (with the user we just created)
    const params = { user };
    const message = await app.service('messages').create({
      text: 'a test',
      additional: 'should be removed'
    }, params);

    assert.equal(message.text, 'a test');
    // `userId` should be set to passed users it
    assert.equal(message.userId, user._id);
    // Additional property has been removed
    assert.ok(!message.additional);
    // `user` has been populated
    assert.deepEqual(message.user, user);
  });
});

Run npm test one more time, to verify that all tests are passing.

Code coverage

Code coverage is a great way to get some insights into how much of our code is actually executed during the tests. Using Istanbul (opens new window) we can add it easily:

npm install nyc --save-dev

Now we have to update the scripts section of our package.json to:

  "scripts": {
    "test": "npm run eslint && npm run coverage",
    "coverage": "nyc npm run mocha",
    "eslint": "eslint src/. test/. --config .eslintrc.json",
    "dev": "nodemon src/",
    "start": "node src/",
    "clean": "shx rm -rf test/data/",
    "mocha": "npm run clean && NODE_ENV=test mocha test/ --recursive --exit"
  },

For TypeScript we also have to install the TypeScript reporter:

npm install @istanbuljs/nyc-config-typescript --save-dev

Add the following .nycrc file:

{
  "extends": "@istanbuljs/nyc-config-typescript",
  "include": [
    "src/**/*.ts",
    "src/**/*.tsx"
  ]
}

And then update the package.json like this:

  "scripts": {
    "test": "npm run compile && npm run coverage",
    "dev": "ts-node-dev --no-notify src/",
    "start": "npm run compile && node lib/",
    "clean": "shx rm -rf test/data/",
    "coverage": "nyc npm run mocha",
    "mocha": "npm run clean && NODE_ENV=test ts-mocha \"test/**/*.ts\" --recursive --exit",
    "compile": "shx rm -rf lib/ && tsc"
  },

On Windows, the coverage command looks like this:

npm run clean & SET NODE_ENV=test& nyc mocha

Now run:

npm test

This will print out some additional coverage information.

Note: When using Git for version control, the .nyc_output/ folder should be added to .gitignore.

What's next?

That’s it - our chat guide is completed! We now have a fully-tested REST and real-time API, with a plain JavaScript frontend including login and signup. Follow up in the Feathers API documentation for more details about using Feathers, or start building your own first Feathers application!