old_contents: from django.urls import reverse
  
  
  def test_send_email_only_works_in_post(http_client):
      response = http_client.get(reverse("send_email"))
      assert response.status_code == 403
  
new_contents: import pytest
  from django.urls import reverse
  
  
  @pytest.mark.django_db
  def test_get_email_form(admin_client, admin_user):
      admin_client.force_login(admin_user)
      resp = admin_client.get(reverse("admin:newsletters_subscription_changelist"), {})
      assert resp.status_code == 200
      assert resp.context_data["submitted"] is False
      assert resp.context_data.get("form")
  
  
  @pytest.mark.django_db
  def test_submit_valid_email_form(admin_client, admin_user):
      admin_client.force_login(admin_user)
  
      data = {"subject": "My Subject", "body": "My Body"}
      resp = admin_client.post(reverse("admin:newsletters_subscription_changelist"), data)
      assert resp.status_code == 200
      assert resp.context_data["submitted"] is True
      assert not resp.context_data["form"].errors
  
  
  @pytest.mark.django_db
  def test_submit_invalid_email_form(admin_client, admin_user):
      admin_client.force_login(admin_user)
      resp = admin_client.post(reverse("admin:newsletters_subscription_changelist"), {})
      assert resp.status_code == 200
      assert resp.context_data["submitted"] is False
      assert resp.context_data["form"].errors
  
subject: Improve tests