This was a surprisingly involved change. Some of the difficulties included
java.util.Optional purposely not being Serializable (so I had to move a
few Optionals in mapreduce classes to @Nullable) and having to add the Truth
Java8 extension library for assertion support.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=171863777
Implement toplevel class that reads in two database backups and displays
diffs.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=168592124
RecordAccumulator builds a set of datastore Entity records from a set of
leveldb logfiles in a directory tree (which is how we receive them for
database backup/restore testing).
This CL also refactors some of the logfile test code out of
LevelDbLogReaderTest so that we can reuse it for building test logs.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=167313553
