When run under GitLab, functional test stdout is all buffered until the test is complete

[sampierson]

e.g. https://allspark.dev.data.humancellatlas.org/HumanCellAtlas/upload-service/-/jobs/18928

Notice that all the command line output from AWS CLI and the HCA CLI is shown first, then all the Python unittest print() statements. These should be interleaved.

An article online suggests running python unbuffered python -u might fix the problem.