Alhadis / Mocha-When

Write BDD-style tests with improved clarity and eloquence.

“What's this?”

This is a drop-in enhancement for Mocha's BDD interface, which adds two small but tangible improvements:

A when() global

This is the same calling describe(), but the description you give is automatically prefixed by "When ":

when("this test is run", () => {
	it('gets prepended with the word "When"', …);
});

Which is a shorter, clearer way of writing:

describe("when this test is run", () => …);

Tests specified by it() actually start with "It "

Mocha makes idiomatic tests fun to write ...

describe("when the app starts", () => {
	it("activates successfully", () => …);
	it("connects to the server", () => …);
	it("receives a valid payload", () => …);
});

... but not as fun to read:

when the app starts
  ✓ activates successfully
  ✓ connects to the server
  ✓ receives a valid payload
  ✓ displays the result

This module fixes such broken language by automatically prefixing each test:

when the app starts
  ✓ it activates successfully
  ✓ it connects to the server
  ✓ it receives a valid payload
  ✓ it displays the result

If a test (or suite) description already includes the expected prefix, it won't be modified. So you needn't worry about stuff like this:

when When the prefix is included
  ✓ it it won't repeat the word "it"
  ✓ it it'll check for contractions too

Usage

1. Add mocha-when to your project's dependencies:

   # Using NPM:
   npm install --save-dev mocha-when
   
   # Or with Yarn:
   yarn add mocha-when

2. Activate it by calling the function it exports:

   require("mocha-when")();

   Or simply pass mocha-when/register to Mocha's require option:

   // In your `.mocharc.js` file:
   module.exports = {
   	require: [
   		"mocha-when/register",
   	]
   };

Caveats

• ESLint won't recognise the when() global, so add it to your globals list.
• Mocha's ui option is assumed to be bdd (the default).
• Tests can be declared without an it prefix using specify().
• The enhancements applied by this module are persistent and irrevocable.