... and generalize it so there's an action before (clearing the old
tests out) in addition to after (displaying the test results).
Also, do for DMdA as for HtDP.
[It will not bother me if we revert this commit. I liked SK's idea and found it easy to implement. I wonder if others will be worried that it is easy to unintentionally leave off the second argument to check-error. I also wonder if it is problematic to add new string constants, like I've done.]
Here is an example:
(check-error (/ 1 0) "/: division by zero")
(check-error (/ 1 0) "divide by zero")
(check-error (/ 1 0))
(check-error 1)
Here is the output:
Ran 4 tests.
2 of the 4 tests failed.
No signature violations.
Check failures:
check-error encountered the following error instead of the expected divide by zero
:: /: division by zero
in ex.rkt, line 2, column 0
check-error expected an error, but instead received the value 1.
in ex.rkt, line 4, column 0
