def METHOD_NAME(self):
    testletter = Newsletter.objects.create(
        title="testletter",
        description="testdesc",
        sent=False,
    )
    self.client.post(
        reverse("newsletters:admin-send", args=[testletter.pk]), {"post": "yes"}
    )
    testletter.refresh_from_db()
    self.assertTrue(testletter.sent)