1. Unit Testing
2. Integration Testing
3. System Testing
4. Acceptance Testing
5. Regression Testing

there r 4 levels of testing
level 0 :: Sanity Testing  test whether build is testable 
or not
level 1 :: Unit testing, Integraion Testing, System Testing
level 2 :: Regression Testing
level 3 :: Final Regression testing or Postmartom Testing

There are only 4 levels of testing

1. Unit Testing 
2. Integration Testing
3. System Testing
4. User Acceptance Testing

1.unit testing 
2.Integration testing
  a)Top down integration testing
  b)Bottom up integration testing
  c)Big Bang integration testing 
  d)Isolation integration testing 
  e)Incremental integration testing 
3.System testing
4.Acceptance testing.

Levels of testing
1.Unit testing
2.Module testing
3.Interation testing
  a)Top down integration testing
  b)Bottom up integration testing
  c)Big Bang integration testing 
  d)Isolation integration testing 
  e)Incremental integration testing 
4.System testing
5.User acceptance testing

Unit Testing -> Integration Testing -> System testing -> 
Acceptance Testing

1. Unit Testing
2. Integration Testing
3. System Testing
4. System Integration Testing
5.  User Acceptance Testing
6.Operability Testing
7.Regression Testing

Levels of testing
1.unit testing and Integration testing comes under to 
developer side
2.system testing
3.user acceptance testing comes under to tester side

There are 4 level of Testing
Level-0----->Testing on intial Build
Level-1----->Testing on stable build
Level-2---->Testing on Modified Build
Level-3---->Testing on Final Build

Unit Testing 
2. Integration Testing
3. System Testing
4. User Acceptance Testing