added coriant 404 test

test/test_classifier_routes.py

+import contextlib
 import json
 import jsonschema
 import pytest
@@ -272,7 +273,6 @@ def test_peer_not_found(client_with_mocked_data):
         headers=DEFAULT_REQUEST_HEADERS)
     assert rv.status_code == 404
 
-import contextlib
 
 def test_coriant_info(client, mocker):
     """
@@ -303,3 +303,25 @@ def test_coriant_info(client, mocker):
     assert rv.is_json
     response_data = json.loads(rv.data.decode('utf-8'))
     assert response_data == expected_response
+
+
+def test_coriant_info_not_found(client, mocker):
+    """
+    just check the correct method is called, but mock out all sql access
+    """
+
+    @contextlib.contextmanager
+    def mocked_connection(ignored):
+        yield None
+
+    mocker.patch(
+        'inventory_provider.db.db.connection', mocked_connection)
+    mocker.patch(
+        'inventory_provider.db.opsdb.get_coriant_path',
+        lambda a, b, c, d: None)
+
+    rv = client.get(
+        '/classifier/coriant-info/aaa/bbb/ccc',
+        headers=DEFAULT_REQUEST_HEADERS)
+
+    assert rv.status_code == 404