Question

Write Mocha tests to check the functionality of the following JS code:

function rgbToHexColor(red, green, blue) {
    if (!Number.isInteger(red) || (red < 0) || (red > 255)) {
        return undefined;
    }

    if (!Number.isInteger(green) || (green < 0) || (green > 255)) {
        return undefined;
    }

    if (!Number.isInteger(blue) || (blue < 0) || (blue > 255)) {
        return undefined;
    }

    return "#" +
        ("0" + red.toString(16).toUpperCase()).slice(-2) +
        ("0" + green.toString(16).toUpperCase()).slice(-2) +
        ("0" + blue.toString(16).toUpperCase()).slice(-2);
}

console.log(rgbToHexColor(13, 14, 15));
console.log(rgbToHexColor());
//console.log(rgbToHexColor(0, 0, 0));
//console.log(rgbToHexColor("13", 14, 15));
//console.log(rgbToHexColor(-13, 14, 15));
//console.log(rgbToHexColor(266, 14, 15));
module.exports = {rgbToHexColor};

Your tests will be supplied a function named 'rgbToHexColor', which takes three arguments. It needs to meet the following requirements:

• Takes three integer numbers, representing the red, green and blue values of an RGB color, each within range [0…255]
• Returns the same color in hexadecimal format as a string (e.g. '#FF9EAA')
• Returns 'undefined' if any of the input parameters are of invalid type or not in the expected range

Answer 1

My tests:

let rgbToHexColor = require("../06.RGBToHex").rgbToHexColor;
let expect = require("chai").expect;

describe("Tests for the RGB TO HEX task", function () {
    describe("General test", function () {
        it("should return #100C0D for (16, 12, 13)", function () {
            expect(rgbToHexColor(16, 12, 13)).to.equal("#100C0D");
        })
    });

    describe("Test lowest possible input: zeros", function () {
        it("test with zeros", function () {
            expect(rgbToHexColor(0, 0, 0)).to.equal("#000000");
        })
    });

    describe("Test highest possible input: 255", function () {
        it("test with 255", function () {
            expect(rgbToHexColor(255, 255, 255)).to.equal("#FFFFFF");
        })
    });

    describe("Invalid input -negative number", function () {
        it("should be undefined", function () {
            expect(typeof rgbToHexColor(-16, 12, 13)).to.equal("undefined");
        })
    });

    describe("Invalid input -negative number", function () {
        it("should be undefined", function () {
            expect(typeof rgbToHexColor(16, -12, 13)).to.equal("undefined");
        })
    });

    describe("Invalid input -negative number", function () {
        it("should be undefined", function () {
            expect(typeof rgbToHexColor(16, 12, -13)).to.equal("undefined");
        })
    });

    describe("Invalid input out of the Range", function () {
        it("should be undefined", function () {
            expect(typeof rgbToHexColor(266, 12, 13)).to.equal("undefined");
        })
    });

    describe("Invalid input: string", function () {
        it("should be undefined", function () {
            expect(typeof rgbToHexColor("266", 12, 13)).to.equal("undefined");
        })
    });

    describe("Invalid input: fractional numbers", function () {
        it("should be undefined", function () {
            expect(typeof rgbToHexColor(3.13, 12, 13)).to.equal("undefined");
        })
    });

    describe("Pad values with zeros", function () {
        it("should pad values with zeros", function () {
            expect(rgbToHexColor(12, 13, 14)).to.equal("#0C0D0E");
        })
    });

    describe("No input test", function () {
        it("no input test", function () {
            expect(rgbToHexColor()).to.be.undefined;
        })
    });
});