text: const assert = require('assert');
  
  const sum = require('../sum');
  
  describe('#sum.js', () => {
  
      describe('#sum()', () => {
          before(function() {
              console.log('before:');
          });
  
          after(function() {
              console.log('after.');
          });
  
          beforeEach(function() {
              console.log('  beforeEach:');
          });
  
          afterEach(function() {
              console.log('  afterEach.');
          });
  
          it('sum() should return 0', () => {
              assert.strictEqual(sum(), 0);
          });
  
          it('sum(1) should return 1', () => {
              assert.strictEqual(sum(1), 1);
          });
  
          it('sum(1, 2) should return 3', () => {
              assert.strictEqual(sum(1, 2), 3);
          });
  
          it('sum(1, 2, 3) should return 6', () => {
              assert.strictEqual(sum(1, 2, 3), 6);
          });
      });
  });