Give acceptable range on assertion failure

[gsnedders]

Currently, the output is indistinguishable from assert_eq!'s:

thread 'bsf::tests::score_examples' panicked at 'assert_ulps_eq!(scores[0], 590.0798357956826, max_ulps = 1)

    left  = 590.0798357956824
    right = 590.0798357956826

', src/bsf.rs:354:9

It would be nicer to give allowable ranges for both left/right based on the variance allowed.

[jonaspleyer]

Hey @gsnedders I have just released a new RC 0.6.0-rc1 which includes many new features. Is this feature request still up to date? This would require quite a deep restructure of approx or at least the introduction of new traits.

[jonaspleyer]

Update: I have also thought about this from a more conceptual point of view. Usually we think about comparisons in arbitrary dimensional spaces Rⁿ. The epsilon value is then the upper limit on values of the metric d:Rⁿx Rⁿ --> R_>=0. Therefore the concept of "left" and "right" variances can not be easily be generalized to higher dimensions or more complex types. This is relevant for the AbsDiffEq and RelativeEq traits but not for the ULPs trait.