. It is a Good news to Developers, but bad news to a tester, coz a tester is supposed to exploit the application and digout the bugs in it.
As in most cases, it depends. There are two situations where one would expect all of the tests to pass. The first is where there are no defects (or very few defects) to find. The second is when many test cases failed in the first few test passes and all of the detected problems were repaired.
It depends on how good your tests were and what they were testing. To have justified confidence in the software we must have confidence in our tests, data and environment.