Explain in detail about Integration testing.
-  It is a systematic method for constructing the program structure. 
 
-  Incremental integration - The program is constructed and tested in small increments. 
 
Top-down integration
-  It is an incremental approach. 
 
-  Modules are integrated by moving downward through the control hierarchy starting with the main control module (main program). 
 
-  Subordinate modules are incorporated by depth-first or breadth-first manner.