- They try to test the code to make sure that it works, rather than testing all the ways in which it doesn’t work.
- Since they wrote it themselves, developers tend to be very optimistic about the software and don’t have the correct attitude needed for testing: to break software.
- Developers skip the more sophisticated tests that an experienced tester would perform to break the software. They follow the happy path to execute the code from start to finish with proper inputs, often not enough to get the confidence to ship software in production.
Thank youuu @danghongnhung