[Pitch] Exit tests

[grynspan (Jonathan Grynspan)]

@jmschonfeld

First, can other expectations be validated during an exit test (for example if I wanted to validated via an #expect or #require that something happened in the separate process as part of a setup step before triggering the crash)?

Yup, in general issue recording "just works".

@jmschonfeld

Additionally, is there room for a convenience that allows explicitly testing precondition/assert failures? Rather than needing to configure stdout yourself and write the correct signal/exit code in your test, I wonder if we could enable writing:

This is something we did look at doing, but decided against (at least in the initial feature implementation) because Swift itself doesn't really define the effects of a precondition failure beyond "abnormal process termination". As implemented, swift::fatalError() calls abort() indiscriminately, which means there's no practical way to distinguish fatalError() from preconditionFailure() without scraping stderr.

There was some discussion on this topic in an earlier thread.