text: const { toUpper:upper, decorateToUpper } = require("../src/index");
  
  describe("Test some function", () => {
      // test
      test("it should make string uppercased", () => {
          expect(upper("UnIcOrNs")).toEqual("UNICORNS");
      });
  
      test("it should make string uppercased and append [decorated] to the end", () => {
          expect(decorateToUpper("UnIcOrNs")).toEqual("UNICORNS [decorated]");
      });
  
      test("mock toUpper()", () => {
          const f = require("../src/index");
          jest.spyOn(f, 'toUpper').mockReturnValue('ccc');
          expect(f.decorateToUpper('aaa')).toBe('ccc [decorated]');
      });
  });
  