Functions 
Use
You can create automatic R/3 and R/2 test cases with the CATT functions in a function editor tailored for CATT requirements.
Prerequisites
Functions can only be created for type C, R and L test cases.
Functions
The following functions exist:
TCD: run and test transactions
REF: refer to other test cases
FUN: call ABAP function modules
TXT: comment
CHETAB: check database contents
CHEVAR: check parameter contents
CHEERR: check system messages
SETVAR: assign values to parameters
IF ... ENDIF: conditions
DO ... ENDDO: loop
SETTAB /
RESTAB: change customizing tables