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);
});