Warn for missing targets

[thim81]

linked to #632 #391

Result:

[thim81]

@nicklloyd

Not sure, what should be the default --warn true or false?

Or this should be default, with an "--strict" instead of "--warn"?

[thim81]

@jpjpjp Got any feedback about the expected behaviour and/or need of having --warn or --strict?

[jpjpjp]

@jpjpjp Got any feedback about the expected behaviour and/or need of having --warn or --strict?

TBH, I'm not sure where the --warn or --strict options come into play. (Are these documented?)

What I like about the behavior as demonstrated in the screenshot is that the collection is still written but at the end of the output you get a clear message that it includes references to undefined "stuff". There may be circumstances where you are writing tests in advance of implementation where this is expected, but I think its ALWAYS good to know that it is occuring.