t.js

it("should multiply the number passed as parameter and subtract one", () => {
  const multiplySpy = spyOn(Calculator, "multiple").and.callThrough();
  const subtractSpy = spyOn(Calculator, "subtract").and.callThrough();
  const result = Calculator.compute(21.5);
  expect(multiplySpy).toHaveBeenCalledWith(21.5, 2);
  expect(subtractSpy).toHaveBeenCalledWith(43, 1);
  expect(result).toBe(42);
});