nebraska: behaviour-based "noupdate" unit test

Instead of testing the internal implementation of how Nebraska handles
update requests when the is no update available, we test the behaviour:
- create an update request of a valid app that does not have an update
- ensure that the response contains <updatecheck status="noupdate"/>

Also use GIVEN/WHEN/THEN format to document the test.

BUG=chromium:920404
TEST=./run_unittests

Change-Id: I63274254cab866e38b5dfb5e7b805aba3be6aa73
Reviewed-on: https://chromium-review.googlesource.com/1650716
Tested-by: Nicolas Norvez <norvez@chromium.org>
Commit-Ready: Nicolas Norvez <norvez@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>
Reviewed-by: Xiaochu Liu <xiaochu@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
1 file changed