Assertion
in software development is technique used to detect and track a state in
program which should not occur. In computer programming it is so called
programming predicate that developer assumes that is always true. The predicate
is Boolean valued function which returns a true–false expression.
Information
about the predicate can be placed into comment of the program code. However it
can be also directly included in the code. While the code is compiled or the
compiled program runs there are checks for these predicates. These do not serve
as treatment of unexpected or err nous states like user input checks. Instead
it is about the detection of the status which is not supposed to happen.
Assertion
or so called checkpoints define points in a program, at which the state of the
program can be tested during program execution. Checkpoints are either
conditional or unconditional. Conditional checkpoints are defined by ASSERT,
unconditional checkpoints by BREAK-POINT or LOG-POINT. Needless to say that the
checkpoint of all types are non-operational statement used just for test
purposes.
Activation/deactivation
of checkpoints outside of the program can be done by assigning them to a
checkpoint group in t-code SAAB.
How
the checkpoints or assertion is supported in ABAP programming language? There
are a couple of ABAP statements for this purpose.
ASSERT statement - it is a checkpoint. It is used to verify specific assumptions about
the status of a program at a specific point. The ASSERT statement is instantly
recognizable for example when analysing ABAP dump.
LOG-POINT statement - is a checkpoint which creates a log entry when
an active logpoint is reached. The logpoint must be assigned to a checkpoint
group. The statement LOG-POINT was introduces to replace wrong usage of the
ASSERT with a condition that is always wrong for simply writing log entries.
BREAK-POINT statement - is placed in the ABAP program. When it is
reached in foreground/dialog processing it branches to the ABAP Debugger. If
the breakpoint is set by user in ABAP editor it has limited validity - until
user logs off. In case the breakpoint is hard-coded with the statement
BREAK-POINT it is considered as unconditional checkpoint with an unlimited
validity which is either always active or activated by assigning it to a
checkpoint group.
More
information:
See
example of LOG-POINT statement usage: github.com/softy12/ABAP-LOGPOINT
Below
see a simple log entry created by LOG-POINT statement.
