public void Select_SourceIsArray_ElementAtOrDefault() { var source = new[] { 1, 2, 3, 4 }.Select(i => i * 2); for (int i = 0; i != 4; ++i) Assert.Equal(i * 2 + 2, source.ElementAtOrDefault(i)); Assert.Equal(0, source.ElementAtOrDefault(-1)); Assert.Equal(0, source.ElementAtOrDefault(4)); Assert.Equal(0, source.ElementAtOrDefault(40)); Assert.Equal(6, source.Skip(1).ElementAtOrDefault(1)); Assert.Equal(0, source.Skip(2).ElementAtOrDefault(9)); }