Some tests check for equality with quite large HTML fragments, when
the test is only interested in certain specific things (and not style
changes etc). This patch alters some of those tests (specifically ones
that were tripping up a dependent patch, but can be expanded) to check
the context data of the response, since the actual rendering is tested
by horizon's tests.
It also adds tests to check context data in 'normal' circumstances so
that no test coverage should be lost by this.
Change-Id: I09be82058edc923521ffb4c022515845a18b158d
Closes-Bug: #1517084