On current master:
2019-01-29T18:04:07.917000Z TestFramework (INFO): Initializing test directory /tmp/test_runner_₿_🏃_20190129_180403/feature_fee_estimation_113
2019-01-29T18:04:10.167000Z TestFramework (INFO): This test is time consuming, please be patient
2019-01-29T18:04:10.167000Z TestFramework (INFO): Splitting inputs so we can generate tx's
2019-01-29T18:04:13.149000Z TestFramework (INFO): Finished splitting
2019-01-29T18:04:14.100000Z TestFramework (INFO): Will output estimates for 1/2/3/6/15/25 blocks
2019-01-29T18:04:14.100000Z TestFramework (INFO): Creating transactions and mining them with a block size that can't keep up
2019-01-29T18:05:32.948000Z TestFramework (INFO): Creating transactions and mining them at a block size that is just big enough
2019-01-29T18:06:45.357000Z TestFramework (ERROR): Assertion failed
Traceback (most recent call last):
File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_framework.py", line 173, in main
self.run_test()
File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-i686-pc-linux-gnu/test/functional/feature_fee_estimation.py", line 234, in run_test
check_estimates(self.nodes[1], self.fees_per_kb)
File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-i686-pc-linux-gnu/test/functional/feature_fee_estimation.py", line 117, in check_estimates
% (feerate, last_feerate))
AssertionError: Estimated fee (0.000565) larger than last fee (0.000479) for lower number of confirms