added test for get_top_level_services

test/test_classifier_utilities.py

 import pytest
 from inventory_provider.routes import classifier
+from inventory_provider.routes.classifier import get_top_level_services
+from inventory_provider.tasks import common
+
 
 @pytest.mark.parametrize('interface_name,base_name', [
     ('ae0', 'ae0'),
@@ -19,3 +22,19 @@ from inventory_provider.routes import classifier
 )
 def test_base_interface_name(interface_name, base_name):
     assert classifier.base_interface_name(interface_name) == base_name
+
+
+# todo - not too keen on this as it relies on the extracted opsdb data, which
+#        could change and lead to this test failing
+def test_get_top_level_circuits(mocked_redis):
+    config = {
+        'redis-databases': 'xxx',
+        'redis': {
+            'hostname': 'host',
+            'port': 1234
+        }
+    }
+    r = common.get_current_redis(config)
+    tls = get_top_level_services(47141, r)
+    assert len(tls) == 1
+    assert tls[0]['name'] == 'LON2-PAR 300G TRUNK'