add invalid test for htmx_create_device_cagetory

devices/tests/test_device_category_form_views.py

@@ -33,3 +33,20 @@ def test_device_category_create_view(create_admin_user):
     response = client.post('/create/devices/category/', data)
     assert (response.status_code == 200
             and helper.in_content(response, 'Foo'))
+
+
+def test_device_category_create_view_invalid_form(create_admin_user):
+    user = create_admin_user()
+    client = Client()
+    client.login(username="pharma-admin", password="password")
+    computer = mixer.blend('computers.Computer', customer=user['customer'])
+    session = client.session
+    session['device_to_update'] = computer.pk
+    session.save()
+    data = {
+        "name": " ",
+        "save_category": "adf",
+    }
+    response = client.post('/create/devices/category/', data)
+    assert (response.status_code == 200
+            and helper.in_content(response, 'This field is required.'))