tags 24402 patch
quit

Alex <agrambot@gmail.com> writes:

> Gemini Lasswell <gazally@runbox.com> writes:
>
>> I’ve done some investigating of why this is happening. testcover-start
>> transforms:
>>     (should-error (my-error))
>> into:
>>     (should-error (testcover-after 2 (my-error)))
>>
>> Then the macro expansion of should-error separates the form which it
>> is passed into a function symbol and list of arguments, and applies
>> the function to the arguments inside of a condition-case that traps
>> errors. The problem is that the arguments are evaluated first, outside
>> of the condition-case, so errors in their evaluation do not get
>> caught. This problem is not specific to testcover. In this example,
>> the first test passes and the second fails:
>>
>> (defun div-by (n)
>>   (/ 100 n))
>>
>> (defmacro log-div-by (n)
>>   `(message "div-by: %d" (div-by ,n)))
>>
>> (ert-deftest test-div-by ()
>>   (should-error (div-by 0)))
>>
>> (ert-deftest test-log-div-by ()
>>   (should-error (log-div-by 0)))
>>   
>
> I just ran into this as well. Consider these two forms:
>
> (should-error (cl-fourth "1234") :type 'wrong-type-argument)
>
> (should-error (car (cdr (cdr (cdr "1234")))) :type 'wrong-type-argument)
>
> Only the second raises an error, even though cl-fourth is equivalent to
> the car/cdr chain.

Here's a diff that appears to fix this. It's a bit crude, but I'd rather
not mess around too much with ert's internals.