all tested have been executed
100% severery bugs are resolved
budget depleated
test schedule

when the build will become bugfree(with out any bugs)then 
we stop testing

After keeping the bugs in the tracking system, related 
development team fixes the bugs. once all the bugs are 
fixed again tester have to again check and close it.then 
the testing process is compleated.

In some companies they keep on testing the project even it 
was released. once if they found any bugs they will fixes 
and upload. it is sutable for some applications only

We need to Priortize the test, when to stop testing. This 
should be made at the rearly stage of testing.

As we cant find a application without bug free, and there 
is no end to stop testing, so the best practise of how good 
the testing can be done is by priortizing what and still 
where we need to test.

You Can't determine when to stop testing. Now a days 
software applications are so complex and should run in a 
interdependent environment that complete 100 % testing can 
never be done. Few things are there to stop....

1. When bug rate falls to certain level
2. Testcases completed with certain percentage passed
3. Depending on Test Budget
4. Deadlines (may be release deadlines or testing deadlines)

when the major functionality will not work in an application
then we will stop testing

When to stop testing" is one of the most difficult 
questions to a test engineer. The following are few of the 
common Test Stop criteria: 

- All the high priority bugs are fixed.
- The rate at which bugs are found is too small.
- The testing budget is exhausted.
- The project duration is completed.
- The risk in the project is under acceptable limit.

Testing should be stopped when all system requirements have 
been met. And all outstandng high risk bugs have been 
addressed

when we completely assure that there is no bug in the
program.this can be done by using bug life cycle.BLC
completely remove the bug from program code