Added unit tests

Author: gavin-aguiar

tests/unittests/test_utilities.py

@@ -6,7 +6,7 @@
 from unittest.mock import patch
 import typing
 
-from azure_functions_worker.utils import common, wrappers
+from azure_functions_worker.utils import common, wrappers, library_importer
 
 
 TEST_APP_SETTING_NAME = "TEST_APP_SETTING_NAME"
@@ -367,3 +367,14 @@ def _unset_feature_flag(self):
             os.environ.pop(TEST_FEATURE_FLAG)
         except KeyError:
             pass
+
+    def test_library_importer_invalid_import(self):
+        sys.path.clear()
+        sys.modules.pop('azure.functions')
+        sys.path.insert(0, self._dummy_sdk_sys_path)
+        common.get_sdk_from_sys_path()
+        functionapp = library_importer.get_azure_function_app()
+        self.assertIsNone(functionapp)
+
+        function = library_importer.get_azure_function_app()
+        self.assertIsNone(function)