To use the –report-refcounts (-r) to detect or debug memory leaks, you must have a debug build of Python. Without a debug build, you will get an error message:
>>> import os.path, sys
>>> directory_with_tests = os.path.join(this_directory, 'testrunner-ex')
>>> defaults = [
... '--path', directory_with_tests,
... '--tests-pattern', '^sampletestsf?$',
... ]
>>> from zope import testrunner
>>> sys.argv = 'test -r -N6'.split()
>>> _ = testrunner.run_internal(defaults)
The Python you are running was not configured
with --with-pydebug. This is required to use
the --report-refcounts option.