The following tests are confirming txn behavior by checking the length of the returned oplog entry; however, with large txns, there are now more oplog entries than in previous implementations. We can see an example of this in this log: https://logkeeper.mongodb.org/lobster/build/fc67f4e0187fcd11f18ac28c94fb6cb9/test/62530636f84ae871871e783c#bookmarks=0%2C4400&l=1

This test fails on line:

jstests/sharding/internal_txns/retryable_writes_oplog_entries.js

https://github.com/10gen/mongo/blob/53eaaa11e4e19029a714c2db6d243af3b5fbbd68/jstests/sharding/internal_txns/retryable_writes_oplog_entries.js#L81

These tests fail on line: 

jstests/sharding/internal_txns/retryable_writes_basic.js, jstests/sharding/internal_txns/retryable_writes_failover.js, jstests/sharding/internal_txns/retryable_writes_restart.js

https://github.com/10gen/mongo/blob/87393ce9bcfe06f8aa93b856474fb77bfb3a5267/jstests/sharding/internal_txns/libs/retryable_internal_transaction_test.js#L226