                expect(emptyArray.arrayByAppending()).to(equal(emptyArray))
                expect(emptyArray.arrayByAppending([])).to(equal(emptyArray))
                expect(nonEmptyArray.arrayByAppending()).to(equal(nonEmptyArray))
                expect(nonEmptyArray.arrayByAppending([])).to(equal(nonEmptyArray))
            }
            describe("arrayByAppending can append one element") {
                expect(emptyArray.arrayByAppending("testko")).to(equal(["testko"]))
                expect(emptyArray.arrayByAppending(["testko"])).to(equal(["testko"]))
                expect(nonEmptyArray.arrayByAppending(5)).to(equal([1, 2, 3, 4, 5]))
                expect(nonEmptyArray.arrayByAppending([5])).to(equal([1, 2, 3, 4, 5]))
            }