Add notification creation check

tests/test_papi.py

@@ -141,6 +141,10 @@ def test_onchange_notification():
     jresp = response.json()
     assert not jresp["notify"]
 
+    notifs = client.get(f"notifications/{id_sonde}/")
+    assert notifs.ok
+    assert len(notifs) == 1
+
 
 class CodeCoverageTestCase(TestCase):