js-test/sum.test.js

'use strict';

const assert = require('assert');
const { sum } = require('./sum');

const test = (description, testProcedure) => ({
    description,
    test: testProcedure,
});

const testSumCorrectness = test(
    '#sum should return the sum of its arguments', 
    () => { 
        const a = 1;
        const b = 2;
        const result = sum(a, b);
        assert(result === a + b, 'the result should be the sum of its arguments');
    }
);

const testSumNoArgs = test(
    '#sum should throw an error if no arguments are passed',
    () => {
        try {
            sum();        
        } catch {
            return;
        }
        assert.fail('should fail if not provided any arguments');
    }
);

const testSumMissingArg = test(
    '#sum should throw an error if no arguments are passed',
    () => {
        const a = 1;
        try {
            sum(a);        
        } catch {
            return;
        }
        assert.fail('should fail if not provided all arguments');
    }
);

const testWillFail = test(
    '#sum will fail against its will',
    () => {
        assert.fail('I have failed!');
    }
);

module.exports = {
    testSumCorrectness,
    testSumNoArgs,
    testSumMissingArg,
    testWillFail,
};