Iterative testing is also called as a datadriven or 
retesting ,it is nothing but testing the functionality ot 
the application with multiple input values

Iterative testing simply means testing that is repeated, or 
iterated, multiple times. Iterative usability testing 
matters because the ultimate goal of all usability work is 
to improve usability, not to catalog problems. A single 
usability test - particularly if no action is taken based 
on its findings - can only tell you how successful or 
unsuccessful you were in creating ease of use. To improve 
upon what you already have, recommendations based on the 
usability test's findings must be incorporated into a 
revision of the product. Once this has been done, it's 
advisable to test the product again to make sure that no 
additional usability flaws were incorporated with the fixes 
to the previously found glitches. In an ideal world, of 
course, this cycle of testing would continue as long as 
meaningful recommendations for improvement could be drawn 
from the usability test results. In reality, it's best to 
define quantifiable goals for your product's usability 
before you begin testing, and to continue the cycle of 
testing and revising until your usability goals have been 
met.