#150: Add test to ensure all required abstract methods are present f…

…or Backend

test/test_backends.py

@@ -1,5 +1,6 @@
 import pytest
 
+from datagateway_api.common.backend import Backend
 from datagateway_api.common.backends import create_backend
 from datagateway_api.common.database.backend import DatabaseBackend
 from datagateway_api.common.icat.backend import PythonICATBackend
@@ -17,3 +18,58 @@ def test_backend_creation(self, backend_name, backend_type):
         test_backend = create_backend(backend_name)
 
         assert type(test_backend) == backend_type
+
+    def test_abstract_class(self):
+        """Test the `Backend` abstract class has all the required classes for the API"""
+        Backend.__abstractmethods__ = set()
+
+        class DummyBackend(Backend):
+            pass
+
+        d = DummyBackend()
+
+        credentials = "credentials"
+        session_id = "session_id"
+        entity_type = "entity_type"
+        filters = "filters"
+        data = "data"
+        instrument_id = "instrument_id"
+        facilitycycle_id = "facilitycycle_id"
+        id_ = "id_"
+
+        assert d.login(credentials) is None
+        assert d.get_session_details(session_id) is None
+        assert d.refresh(session_id) is None
+        assert d.logout(session_id) is None
+        assert d.get_with_filters(session_id, entity_type, filters) is None
+        assert d.create(session_id, entity_type, data) is None
+        assert d.update(session_id, entity_type, data) is None
+        assert d.get_one_with_filters(session_id, entity_type, filters) is None
+        assert d.count_with_filters(session_id, entity_type, filters) is None
+        assert d.get_with_id(session_id, entity_type, id_) is None
+        assert d.delete_with_id(session_id, entity_type, id_) is None
+        assert d.update_with_id(session_id, entity_type, id_, data) is None
+        assert (
+            d.get_facility_cycles_for_instrument_with_filters(
+                session_id, instrument_id, filters,
+            )
+            is None
+        )
+        assert (
+            d.get_facility_cycles_for_instrument_count_with_filters(
+                session_id, instrument_id, filters,
+            )
+            is None
+        )
+        assert (
+            d.get_investigations_for_instrument_facility_cycle_with_filters(
+                session_id, instrument_id, facilitycycle_id, filters,
+            )
+            is None
+        )
+        assert (
+            d.get_investigation_count_instrument_facility_cycle_with_filters(
+                session_id, instrument_id, facilitycycle_id, filters,
+            )
+            is None
+        )