rspec 3.13: breaking changes to ExpectedsForMultipleDiffs

[jas14]

It appears that in rspec 3.12, have_attributes was an aliased matcher, but no longer is. I haven't tracked down the precise source of the change, but I added an Appraisal set for RSpec 3.13.0 and tests are failing.

EDIT: I think I misdiagnosed – the issue may be the rename from RSpec::Matchers::{ExpectedsForMultipleDiffs -> MultiMatcherDiff }, see rspec/rspec-expectations@81d3a58 .

EDIT 2: it's both. 😭

[jas14]

Suspect: rspec/rspec-expectations@3d97c7e

AliasedMatcher now delegates almost everything – including and especially .is_a? – to the underlying matcher. Differs::ObjectHavingAttributes therefore no longer applies to the matcher: https://github.com/mcmire/super_diff/blob/fc418c15f04925e00f32298fc85f74c57591fc69/lib/super_diff/rspec.rb#L45