I've built @psunkara test suite (here: https://github.com/framp/connect-union) for connect and union (following what he did with the previous version) and fixed the trivial bug of originalUrl.
It looks like both req.url and req.originalUrl are being used.
There are still 7 errors according to the test, but I'm not sure if they're bugs specific to union or simply differences between flatiron and connect (as I'm not familiar with the codebase)
FIX: add originalUrl to support connect>2.3.5
This pull request passes (merged 94da26a into c7f7ac9).