diff --git a/tests/test_geometry_factory.py b/tests/test_geometry_factory.py
index 58d15ee5..081aa3d4 100644
--- a/tests/test_geometry_factory.py
+++ b/tests/test_geometry_factory.py
@@ -10,6 +10,8 @@ from unittest import TestCase
 from city_model_structure.city import City
 from factories.geometry_factory import GeometryFactory
 from helpers.geometry_helper import GeometryHelper
+import math
+import numpy as np
 
 
 class TestGeometryFactory(TestCase):
@@ -86,6 +88,19 @@ class TestGeometryFactory(TestCase):
         errors += 1
     print(f'{errors} buildings aren\'t closed volumes')
 
+  def test_volume(self):
+    """
+
+    :return:
+    """
+    building = 'bld100087.gml'
+    file_path = (self._example_path / building).resolve()
+    city = GeometryFactory('citygml', file_path).city
+    for building in city.buildings:
+      print('volume', building.volume)
+      #print('volume om', building.volume_om)
+      building.stl_export(self._output_path)
+
   def test_citygml_buildings(self):
     """
     Test city objects in the city
@@ -222,3 +237,13 @@ class TestGeometryFactory(TestCase):
                               'thermal_opening front_side_solar_transmittance_at_normal_incidence was initialized')
             self.assertIsNone(thermal_opening.thickness, 'thermal_opening thickness_m was initialized')
             self.assertRaises(Exception, lambda: thermal_opening.u_value, 'thermal_opening u_value was initialized')
+
+  def test_is_planar(self):
+    building = 'bld100087.gml'
+    file_path = (self._example_path / building).resolve()
+    city = GeometryFactory('citygml', file_path).city
+    for building in city.buildings:
+      for surface in building.surfaces:
+        print(surface.type, surface.area)
+      print('volume', building.volume)
+