[test] adding test for converting nested type

tests/unit/stream_alert_rule_processor/test_classifier.py

@@ -13,7 +13,7 @@
 See the License for the specific language governing permissions and
 limitations under the License.
 """
-# pylint: disable=protected-access
+# pylint: disable=protected-access,too-many-public-methods
 import json
 
 from mock import call, patch
@@ -84,6 +84,19 @@ def test_convert_type_invalid_int(self, log_mock):
             'key_01',
             'NotInt')
 
+    @patch('logging.Logger.error')
+    def test_convert_type_invalid_nested(self, log_mock):
+        """StreamClassifier - Convert Type, Invalid Nested Type"""
+        payload = {'key_01': '100', 'streamalert:envelope_keys': {'host': 'NotInt'}}
+        schema = {'key_01': 'integer', 'streamalert:envelope_keys': {'host': 'integer'}}
+
+        assert_false(self.classifier._convert_type(payload, schema))
+
+        log_mock.assert_called_with(
+            'Invalid schema. Value for key [%s] is not an int: %s',
+            'host',
+            'NotInt')
+
     def test_convert_type_valid_float(self):
         """StreamClassifier - Convert Type, Valid Float"""
         payload = {'key_01': '12.1'}