The Compare close contains a close method that checks to see if there
is any unconsumed data in the Compare instance; i.e. if the canonical
output file contains more data than was produced by the current test
run. This method was never called, allowing differences to go
undetected.

Fix is to call close after the test is run (after __import__)

output/test_long and output/test_popen2 needed trivial changes
output/test_select contained lots of text, but test_select.py produced
    no output