chocolatest

Chocolatest

A simple and tiny test framework that evaluates synchronous javascript (for now) in the browser

npm i -S chocolatest

Usage

import { generateEvaluator, Reporter } from 'chocolatest';

const evaluator = generateEvaluator(new Reporter());

const src = `
  //define the function below
  const isPrime = (n) => {
    return n === 2;
  };
`;

const tests = `
  test('returns true for prime numbers', () => {
    assert(isPrime(2));
    assert(isPrime(3));
    assert(isPrime(5));
    assert(isPrime(7));
    assert(isPrime(23));
    assert(isPrime(24), 'must fail, 24 not prime');
  });
`;

const report = evaluator.run(src, tests);

Outputs (rendering the Report object to HTML)

Ran 6 assertions in 1 tests

Asserts passed 1

Asserts failed 5

Tests passed 0

Tests failed 1

• returns true for prime numbers
  • Expected: true Actual: false
  • Expected: true Actual: false
  • Expected: true Actual: false
  • Expected: true Actual: false
  • Expected: true Actual: false Message: must fail, 24 not prime

API

The assertion api is best described in one of the two dependencies chocolatest uses.
Browserify's commonjs-assert module

And the method to group assertions is test(name: string, body: () => void)
as you have already seen in the example. Note that you can have more than one call to
test for every run.

Report object

interface Report {
  testsCount: number;
  testsPassed: number;
  testsFailed: number;
  testsFailedDetails: {
    id: number;
    name: string;
    failures: AssertionEntry[];
  }[];
  assertsCount: number;
  assertsPassed: number;
  assertsFailed: AssertionEntry[];
}

interface AssertionEntry {
  id: number;
  test: number;
  expected: any;
  actual: any;
  message: string;
}

From here you can format the report the way you like and show it to the user.

How it works (in case you want to know)

It leverages on the use of the commonjs-assert module by browserify as long with the vm-browserify module that allows to
safely execute javascript as a string within a given context and some meta programming using javascript's Proxy object.
You can a look to the src, specifically proxied-assert.ts.
In case you want to know more about proxies and meta programming I deeply recommend Dr. Axel Rauschmayer's post.

License

MIT © Nico Gallinal