Testsuite driver buffering behavior has changed with Python 3
The buffering behavior of the testsuite driver has changed with the move to Python 3 (#9184 (closed)). Now output seems to arrive at the terminal in blocks. This is strange since the documentation for
sys.stdout in Python 3.5 claims,
When interactive, standard streams are line-buffered. Otherwise, they are block-buffered like regular text files. You can override this value with the
It would be good to understand why this is the case.