text: const {
  	validMathOperators,
  	validOperatorsArray
  } = require('../../lib/helpers/valid-math-operators');
  
  describe('valid-math-operators', () => {
  	test('validMathOperators should invoke a function when a valid operator is provided', () => {
  		let mathOperator = '+';
  		let [a, b] = [3, 3];
  		let addition = validMathOperators[mathOperator];
  		let answer = addition(a, b);
  		expect(answer).toEqual(6);
  	});
  	test('validOperatorsArray should return an array of keys from an object.', () => {
  		let mathObject = {
  			'+': 'addition',
  			'-': 'subtraction',
  			'/': 'division',
  			'*': 'multiply'
  		};
  		let array = validOperatorsArray(mathObject);
  		expect(array).toEqual(['+', '-', '/', '*']);
  	});
  });
  