Add helper function to create test data,
reduce amount of unrelated details
Reduced complicated logic in tests, in particular
move most of expectation inside the tests from helpers.
Bug: None
Change-Id: I53f29a70989086c7628a0b112a45ec4567b40bf9
Reviewed-on: https://webrtc-review.googlesource.com/100380
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24760}
55bb00e4c2