Unit testing and system testing
Unit testing refers to trials made to individual components of hardware or software. For example, when a program is developed, in-house unit test for each program in the system is conducted to test the interface between individual programs in the system.
System testing refers to thorough test performed on the system as a whole. It involves tests or trials on the system intended to sort out major bugs or problems using dummy or invented data so as to test all conditions. For example, dummy test data records should be input which is designated to test all the data validation routines and master file update error reports in the system.