pytests: Add test for object required but path non existent

Signed-off-by: Monika Kairaityte <monika@kibit.lt>

pytests/test_container_to_args.py

@@ -352,6 +352,15 @@ class TestContainerToArgs(unittest.IsolatedAsyncioTestCase):
             ],
         )
 
+    async def test_env_file_obj_required_non_existent_path(self):
+        c = create_compose_mock()
+
+        cnt = get_minimal_container()
+        cnt['env_file'] = {'path': 'not-exists', 'required': True}
+
+        with self.assertRaises(ValueError):
+            await container_to_args(c, cnt)
+
     async def test_env_file_obj_optional(self):
         c = create_compose_mock()