test("basic functionality", () => { expect(Math.cos).toHaveLength(1); expect(Math.cos(0)).toBe(1); expect(Math.cos(null)).toBe(1); expect(Math.cos("")).toBe(1); expect(Math.cos([])).toBe(1); expect(Math.cos(Math.PI)).toBe(-1); expect(Math.cos()).toBeNaN(); expect(Math.cos(undefined)).toBeNaN(); expect(Math.cos([1, 2, 3])).toBeNaN(); expect(Math.cos({})).toBeNaN(); expect(Math.cos("foo")).toBeNaN(); expect(Math.cos(-Infinity)).toBeNaN(); expect(Math.cos(Infinity)).toBeNaN(); });