The Oracle BI Baseline Validation Tool enables you to identify differences during life cycle operations, such as migrating from the Oracle BI 11g release to the 12c release (or regression testing).
It became available with release 12, to support and improve the tedious process of upgrade validation. To the best of my knowledge, it's free with OBIEE.
Baseline Validation Tool is a command line tool, available for Windows and Linux.
I was very surprised lately that many of my customers were unaware of it.
So here is the download link. The documentation is part of the download.
You can find many blogs covering the subject such as enterprisebisolution, here (no part 2) and vlamis, here or a short introduction on YouTube.