Tester or not, the expertise on developing quality code depends upon one's own programming skills and constant or continuous learning in that area.
Some people, though in testing projects, take time out of their work to improve their programming skills by contributing to coding efforts or taking up projects voluntarily.
Thus, being a Tester does not prevent you in any way from being an expert Programmer or Vice Versa!!!
One way to narrow the communication gap between Tester & Developer community is to include the Testing teams, right from the Requirements/Design Stage meetings so that everyone involved in the life cycle of developing a software product can take part in the discussion & offer valuable suggestions.
This is evident from the below lines, which wonderfully describes the importance of Testing
More than the act of testing, the act of designing tests is one of the best bug preventers known. The thinking that must be done to create a useful test can discover and eliminate bugs before they are coded - indeed, test-design thinking can discover and eliminate bugs at every stage in the creation of software, from conception to specification, to design, coding and the rest. -Boris Beizer, Software Testing Techniques, "Creating a Software Engineering Culture" by Karl Eugene Wiegers"
