= NAME =
assert_define

= SYNOPSIS =
 * assert_define <varname> ["message words"]


= DESCRIPTION =
This function checks that the indicated variable is defined.  Otherwise,
it aborts the currently running test.

An optional message can be provided for the abort call.


= EXAMPLES =
Here are some sample invocations:
{{{#!YellowBox
    assert_define FUNCTIONAL_BC_EXPR
    assert_define FUNCTIONAL_BC_RESULT
}}}

{{{#!YellowBox
    is_on_target bc BC_PROGRAM /bin:/usr/bin:/usr/local/bin
    assert_define BC_PROGRAM "Missing program 'bc' on target"
}}}

This second example shows use of assert_define following a call to is_on_target,
as well as the use of an optional message if the variable is not defined.


= ENVIRONMENT and ARGUMENTS =
The positional arguments to assert_define are:
 * $1 - the variable to check the definition of
 * $2 - an optional message to use if the variable is not defined


= RETURN =
Returns non-zero on error.

= SOURCE =
Located in ''scripts/functions.sh''

= SEE ALSO =
 * [[function_test_pre_check|test_pre_check]], [[function_is_on_target|is_on_target]]