Refactor document views specs

https://www.pivotaltracker.com/story/show/73291456
Summary of changes: https://docs.google.com/document/d/13TNmNkD6__d-7TbnvkNUV8yvCY8bc_SGa6ewxewrciE/edit?usp=sharing
RSpec 3 encourages us to explicitly specify the types. But there is an option which we can set in the spec_helper to let it figure out the type from the file path.