1 00:00:00,120 --> 00:00:04,280 So let's have a small quiz and see whether you can remember why can testing 2 00:00:04,280 --> 00:00:06,250 guarantee that that a refactoring is behavior is 3 00:00:06,250 --> 00:00:08,590 preserving. So why testing can only show the 4 00:00:08,590 --> 00:00:11,080 absence of defects and not their presence? 5 00:00:11,080 --> 00:00:12,960 Is that because testing and refactoring are different 6 00:00:12,960 --> 00:00:15,980 activities? Because testing is inherently incomplete? Or, just 7 00:00:15,980 --> 00:00:19,560 because testers are often inexperienced? Make your choice.