should-error
should-error is a Lisp macro in `ert.el
'.
(should-error FORM &rest KEYS &key TYPE EXCLUDE-SUBTYPES)
Evaluate FORM and check that it signals an error.
The error signaled needs to match TYPE. TYPE should be a list
of condition names. (It can also be a non-nil symbol, which is
equivalent to a singleton list containing that symbol.) If
EXCLUDE-SUBTYPES is nil, the error matches TYPE if one of its
condition names is an element of TYPE. If EXCLUDE-SUBTYPES is
non-nil, the error matches TYPE if it is an element of TYPE.
If the error matches, returns (ERROR-SYMBOL . DATA) from the
error. If not, or if no error was signaled, abort the test as
failed.