testing happens in various levels..
like
level 0 : sanity testing/Build verification testing/Tester 
Acceptance Testing
level 1 : is comprehensive testing 
level 2 : is regression testing
level 3 : is Acceptance testing.

in level 0 : all p0 testcases are executed
level 1 : All p0, p1 and p2 testcases as batches
level 2 : selected p0, p1 and p2 testcases w.r.to 
modification
level 3 : selected 0, p1, and p2 testcases w.r.to bug 
densitry

comprehensive testing...after level 0 testing and selection 
of possible testcases for automation, test engineers 
concetrate on test suite and test set. every test batch 
consists of a set of dependent testcases.during these test 
batch execution test engineers create test log document 
with these types of entries like no. of pass, failed and 
blocked.
{during comprehensive test execution, test engineers are 
reporting mismatches to developers as defects. After 
resolution of the bug, developers release modified build to 
testers. testers reexecute their test to ensure bug fix 
work and occurences of side effects }...is is according to 
mindq material i had gone thru...if wrong plz do 
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