Add integration/systems tests

[gbp]

While rebasing commits for #60 I inadvertently broke some commits but the test suite stayed green. This shows an issue with our test suite which stems from a new convention in Rails to prefer integration/system tests over controller tests.

We could include the rails-controller-testing gem to do things the old way but as we are trying to do things the right/modern way for this project it makes sense to add a few systems test for the FOI workflow.

[garethrees]

Noting #103