deps

// my npm dep tree (fake, made of lies)
myproject
├─┬ mydep@A.B.C
│ └── bluebird@X.Y.Z
└── bluebird@M.N.O

test-prologue.js

// this is a file that all of my tests require.
for (var key in require.cache) {
  if (require.cache[key].exports &&
            require.cache[key].exports.onPossiblyUnhandledRejection) {
      require.cache[key].exports
        .onPossiblyUnhandledRejection(throwRejectedPromise)
    }
}

function throwRejectedPromise (err) {
  throw err
}

// I have to do this because sometimes I'm returning promises
// generated by "mydep" and ".then"-ing them in my tests — which
// means errors thrown by failed assertions in them will go to
// bluebird@X.Y.Z's unhandledRejection handler.
//
// At other times I'm returning promises from my own library, and
// errors that happen in those ".then" handlers will go to 
// bluebird@M.N.O's unhandledRejection handler.
//
// Yes, `dedupe` can solve this for a lot of cases, but:
// - some folks pin deps and thus they're not dedupable
// - sometimes deps are dedupable, but different versions of npm
//   will build different dep trees (npm@3 is great at flattening!
//   but not all npms are equal in this regard.)
// - the other option is to wrap-ish all promises coming out of my
//   library, which is ... kind of a no-go