mduan

OP here. In our front-end tests, I haven't really noticed cases where the mocks get out of date that don't cause the test cases using the mock to fail, at which point we'd update the mock data. We also have end-to-end Selenium tests as supplement to our front-end tests which helps with catching format mismatch between front-end and backend (granted they're not that comprehensive at the moment).

Since we're on the subject of Github's diff viewer, thought I'd throw in a plug for a chrome extension I wrote recently to improve it:

https://chrome.google.com/webstore/detail/github-enhancement...

Has side-by-side + word wrap + context (somewhat nicer looking than Github's, although could be biased)

Largely inspired by Phabricator's diff viewer.