tests/basics/io_stringio_truncate: Test for uio.StringIO.truncate().
tests/basics/io_stringio_truncate: Test for uio.StringIO.truncate().

Change-Id: If253e9150e9ca216407dc45bb9a291f292eea845
Signed-off-by: Paul Sokolovsky <9dc5061f178bb11813e14f1ed02ba27eaf21fa5d@users.sourceforge.net>

pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython