assertion statement(A Boolean statement used in a program to test a condition that, if the program is operating correctly, should always evaluate as true; otherwise the program will typically terminate with an appropriate error message. Assertions are used for debugging programs and for documenting how a program should operate)
assertion failure(The inability of a condition to hold true at some particular point in a program. When a condition does not hold true, execution of the program is interrupted, and a dialog box or message may appear)