Integration means a module to which an implementation is 
applied for the new feature request or a functionality 
which is dependent on the previous code. 

Now when the new code for the new feature request been 
implemented on the old code we check for the basic 
functionality of the old and and then check for the 
functionality of the newly merged code. If the 
implementation is correct as per the expected result then 
the fix is fine for the functionality

integration testing means testing an application to verify 
the data flows between the module.for example, when you are 
testing a bank application ,in account balence it shows the 
100$as the available balence.but in database it shows the 
120$.

main thing is "integration done by the developers and 
integration testing done by the testers"

Hi, 
   Integration testing is the technique in which we combine
the unit modules which have been already tested.

Nitin is right.

Thanks Rituparna i really oblized.

Integration testing is process of testing one are more 
units otherwise combination(integrating) of two r more 
units is call integration testing.....

Integration testing is of 2 types
1)non incrimental testing
a)Bigbang integration this is a non incrimental model

2)incrimental testing
a)Topdown integration(has 2 types)(stubs are required)
   i)DFS (depth first search)
  ii)BFS (bredth first search)
b)Bottom up testing (drivers are required)
c)sanwitch testing (this is the combination of both topdown 
and bottomup testing)

In integration testing we mainly test the interfaces b/w 
the module, there are 4 types of intigration testing.
1.bottom up 
2. top down
3.critical part first
4.big bang