    def run_tests(self):
        # pytest may be not installed yet
        import pytest
        args = ['--forked', '--fulltrace', '--no-cov', 'tests/']
        if self.test_suite:
            args += ['-k', self.test_suite]
        sys.stderr.write('setup.py:test run pytest {}\n'.format(' '.join(args)))
        errno = pytest.main(args)
        sys.exit(errno)