Prefer stubs to openstructs and singleton methods
Prefer stubs to openstructs and singleton methods

Stubs are more clearly understood than `define_singleton_method`. By
using a real request, we loosen the coupling between the test and the
implementation in that we no longer need to use `request.fullpath` and
the test should still work.

alphagov/collections,alphagov/collections,alphagov/collections,alphagov/collections