def test_packages_intersection(self):
p1 = Package("foo")
p2 = Package("bar")
p3 = Package("baz")
p4 = Package("qux", 123)
p5 = Package("qux")
c1 = PackagesCollection([p1, p2, p3, p4])
self.assertEqual(c1.intersection([p1, p3]).sorted("name"), PackagesCollection([p1, p3]).sorted("name"))
self.assertEqual(c1.intersection(None), c1)
self.assertIsNotNone(c1.intersection([p5])[0].modified)
