implementar funcion getItems en una lista secuencial

`Script const math = require("./math"); test("Should calculate total with tip", () => { const total = math.calculateTip(10, 0.3); expect(total).toBe(13); // if (total !== 13) { // throw new Error("Total tip should be 13. Got " + total); // } }); test("Should calculate total with default tip", () => { const total = math.calculateTip(10); expect(total).toBe(12.5); });`