Add an exception translation mechanism + the ability for users to extend it with custom exception types

[RaviGaddipati]

In some cases a test will fail because an exception is thrown. Right now it just says
"TEST CASE FAILED! (threw exception)"
It would be very helpful if it says what exception is thrown and the message.

[onqtam]

this is planned - also the user will be able to extend the reporting by teaching the framework about custom exception types.

[RaviGaddipati]

Great, loving the framework so far!

[arximboldi]

Related: I would like to prevent Doctest from catching the exception alltogether, so the program crashes and the backtrace is shown directly in the debugger.

[onqtam]

@arximboldi I might add a configuration identifier for this

[arximboldi]

Makes sense, thanks!

[onqtam]

This should be done in the dev branch - docs also in the dev branch!

Also the request of @arximboldi has been added to the roadmap but no ETA on it.

[onqtam]

@arximboldi do you think that using DOCTEST_CONFIG_NO_EXCEPTIONS will be sufficient for your needs? it's already in the library and I don't want to complicate matters any further with more configuration options...

[arximboldi]

Aha! no, but DOCTEST_CONFIG_NO_TRY_CATCH_IN_ASSERTS which I found in the same document is enough for me indeed. Sorry I missed that and thanks!

[onqtam]

@arximboldi but using only DOCTEST_CONFIG_NO_TRY_CATCH_IN_ASSERTS will still result in exceptions thrown from a test case (or assert evaluation) being caught by the test runner and I don't think there will be a backtrace in that case...

[arximboldi]

Oh I missed that. I will try the other one then. I wonder if that will also make tests that check that an exception is thrown fail? But I guess those are just disabled, which is fine most of the time. This may not cover the case where you have a test checking an exception, an except different type is thrown, and you want to get the backtrace of where that comes from. Also, it would be nice to not have to recompile to do this... But all this is icing on the cake, I think this is good all for now.

[onqtam]

@arximboldi When using DOCTEST_CONFIG_NO_EXCEPTIONS the REQUIRE asserts and asserts that deal with exceptions (xxx_THROWS / xxx_THROWS_AS / xxx_NOTHROW) are gone - meaning that using them will result in a compilation error. Thats what DOCTEST_CONFIG_NO_EXCEPTIONS_BUT_WITH_ALL_ASSERTS is for - it makes REQUIRE act like CHECK and the exception macros are turned into a no-op.

I'm not sure that introducing a new identifier to circumvent catching exceptions in the test runner is actually even possible without disabling other functionality - REQUIRE macros throw an exception to terminate the current test case (unlike CHECK). I could have a try/catch only for doctest::detail::TestFailureException - and if I don't catch it there (but instead end up in the default (...) catch clause) I could just rethrow the exception so the program crashes - but in that case I'm not sure what you'll get in the backtrace - the point of rethrowing or the point of the original exception...

If you test this in a simple program and get the full backtrace even after rethrowing from a lower frame in the callstack then I might add a separate identifier - otherwise I'd advice using DOCTEST_CONFIG_NO_EXCEPTIONS.

Also note that in version 1.2 there will be crash handling support - using signals under UNIX - and if a signal is caught doctest will report the current test case and subcases (and I might even add in the future the ability to print which was the last assert that passed successfully for additional context)