Simple Test Tutorial

Calculator.js

class Calculator {
    constructor() {

    }

    add(a, b) {
        return a + b;
    }

    sub(a, b) {
        return a - b;
    }

    mul(a, b) {
        return a * b;
    }

    div(a, b) {
        if( b == 0) {
            throw Error("Cannot be zero!");
        }
        return a / b;
    }
}


module.exports = Calculator;

test.js

// Usage: $ node test.js

const Calculator = require("./Calculator");
const assert = require("assert");

const cal = new Calculator();

function test_add() {

    for (let i = 0; i < 100; i++) {
        const a = Math.random();
        const b = Math.random();

        assert.strictEqual(cal.add(a, b), a + b);
    }

    console.log("ADD PASS!!!!");
}

function test_sub() {

    for (let i = 0; i < 100; i++) {
        const a = Math.random();
        const b = Math.random();

        assert.strictEqual(cal.sub(a, b), a - b);
    }

    console.log("SUB PASS!!!!");

}

function test_mul() {

    for (let i = 0; i < 100; i++) {
        const a = Math.random();
        const b = Math.random();

        assert.strictEqual(cal.mul(a, b), a * b);
    }

    console.log("MUL PASS!!!!");

}

function test_div() {

    for (let i = 0; i < 100; i++) {
        const a = Math.random();
        const b = Math.random();

        assert.strictEqual(cal.div(a, b), a / b);

        assert.throws(() => {
            cal.div(a, 0);
        });
    }

    console.log("DIV PASS!!!!");

}

function test_main() {
    test_add();
    test_sub();
    test_mul();
    test_div();
    console.log("ALL PASS!!!!");
}


test_main();

This code is for the Youtube video tutorial: 如何寫程式測試