Setting up a simple testing suite

30 October 2016
testing

You may want to have your own simple test runner to ensure your functions return accurate results.

I used Mocha and Chai. Here's some sample code and a walk through for using it. Note: the challenge I wrote these tests for was return the sum of all multiples of 3 or 5 that are below a number N, where N is an input parameter to the function.

var should = require("chai").should();
var basic = require("./multJacksonBates");

describe("basic", function () {
	it("should return 23 when passed 10", function () {
		basic(10).should.equal(23);
	});
	it("should return 78 when passed 20", function () {
		basic(20).should.equal(78);
	});
	it("should return 2318 when passed 100", function () {
		basic(100).should.equal(2318);
	});
	it("should return 23331668 when passed 10000", function () {
		basic(10000).should.equal(23331668);
	});
	it("should return 486804150 when passed 45678", function () {
		basic(45678).should.equal(486804150);
	});
});

Walk through #

Pre-req: Install Node & NPM, you can open and type in your OS's terminal / command line

Create a directory for your algorithms and testing, eg: mkdir algos
Navigate to said directory: cd algos
npm init and accept all defaults
npm install -g mocha
npm install mocha chai --save
Write a function you want to test, and export it:

// multJacksonBates.js
function multJacksonBates(n) {
	return 23;
}

module.exports = multJacksonBates;

Notice the code snippet for the test script requires the multJacksonBates function created here and names it basic
Test the script with mocha test.js
It should say the first test passed because it is hardcoded to return the right answer for basic(10).
Write different code in the function so that it passes all test cases. And change the name of the function.
You can add more functions and more tests by replicating the code snips above.

Additional resources #

If you decide to write several functions and want to test them for efficiency, you can modify the benchmark script from here: Benchmark

You can find more information about Mocha and Chai at the following links:

Mocha
Chai