PyHamcrest not catching SystemExit exception

test_exit.py

import sys
import unittest
from hamcrest import assert_that, calling, raises
import pytest


def call_exit():
    sys.exit()


class TestUnittest(unittest.TestCase):
    def test_exits(self):
        with self.assertRaises(SystemExit):
            call_exit()


def test_pytest():
    with pytest.raises(SystemExit):
        call_exit()


def test_hamcrest():
    assert_that(calling(call_exit), raises(SystemExit))

Results in test test_hamcrest tests failing (and others passing).