Multiple output matchers

[killercup]

As commented in #16 (review), I think it might be nice to support multiple output matchers. I'm thinking of having either one exact output matcher, or a list of fuzzy matches.

There might also be a nice way of parameterizing the Assert struct so that only Assert<NoOutputAssert> has .prints_exactly(), and both Assert<NoOutputAssert> and Assert<FuzzyOutputAssert> have .prints().

[colin-kiegel]

I'm also having some very early sketchy thoughts for generalizing the concept. Maybe tomorrow I can write them up. :-)

[epage]

Not sure about when this was first filed, but assert_cli now has .is for exact match and .contains for substring matching. These can also be repeated.

I feel like that should cover most cases. Probably the main additions I can think of are regex and an fn.

[epage]

Huh, not sure why I didn't close this. We have exact and subset matches now. If #98 moves forward with using the predicates crate, we'll have untold opportunities for more.

[epage]

The responsibility for this has moved to assert_cmd / predicates-rs and more than handles the need for this, including an open API design for customization.