10.34.5 Tests and Production Systems

Most applications do not want the test-suite to end up in the final application. There are several ways to achieve this. One way is to place all tests in separate files and not to load the tests when creating the production environment. Another way is to wrap each unit test box in a pair of :- if(…), :- endif directives. For example, the test could be whether the plunit module has been loaded:

:- if(current_module(plunit)).
:- begin_tests(Unit[,Options]).
…
:- end_tests(Unit).
:- endif.

Alternatively, you can reserve a system property e.g. enable_unit_tests to control whether unit tests should be enabled. The property is enabled if you run SICStus Prolog as:

% sicstus -Denable_unit_tests=true

Then your Prolog source file could have the structure:

:- use_module(library(system), [environ/2]).

…

:- if(environ(enable_unit_tests, true)).
:- use_module(library(plunit)).
:- begin_tests(Unit[,Options])
…
:- end_tests(Unit)
:- endif.