When packaging a library, should I prevent its test suite from being packaged

[Konstantin Khomoutov <flatworm@users.sourceforge.net>]

I'm packaging a Python3-only library, PyMySQL [1], for internal usage,
chiefly using

  dh $@ --with python3 --buildsystem=pybuild

This library includes a test suite, in a subdirectory named "tests",
within its source tree.  This directory gets packaged, installed and
byte-compiled (by the generated postinst script) during the
installation.

Having the test suite packaged along with the code looks like having
not much sense to me, so should I try to exclude this subdirectory from
packaging?  Is it considered a bad practice?  I don't have much
familiarity with Python, let alone packaging its libraries, so I'm not
sure if removing such files will break the library or not and what
seasoned Python packagers do in cases like this.

Please CC me as I'm not subscribed.

1. https://pypi.python.org/pypi/PyMySQL