Improve sanity checking of interdiff test opcodes, and fix a test.

Review Request #8831 — Created March 20, 2017 and submitted — Latest diff uploaded

Information

Review Board
release-2.0.x
7959e80...

Reviewers

This improves our interdiff opcode sanity-checking, making sure that
ranges are of the correct lengths. That also unveiled a problem with one
of our tests that had a bad length. That unit test has been fixed
accordingly.

Tested each of the failure paths.

Unit tests pass.