diff --git a/boundaries/tests/test_boundary.py b/boundaries/tests/test_boundary.py
index f79ce07..3770d46 100644
--- a/boundaries/tests/test_boundary.py
+++ b/boundaries/tests/test_boundary.py
@@ -135,5 +135,11 @@ def test_unary_union(self):
         boundary = Boundary(shape='MULTIPOLYGON (((0 0,0 5,2.5 5.0001,5 5,0 0)))')
         boundary.unary_union(Geometry(OGRGeometry('MULTIPOLYGON (((0 0,5 0,5 5,0 0)))')))
 
-        self.assertEqual(boundary.shape.ogr.wkt, 'MULTIPOLYGON (((5 5,5 0,0 0,0 5,2.5 5.0001,5 5)))')
-        self.assertEqual(boundary.simple_shape.ogr.wkt, 'MULTIPOLYGON (((5 5,5 0,0 0,0 5,5 5)))')
+        self.assertEqual(
+            boundary.shape.ogr.difference(OGRGeometry('MULTIPOLYGON (((5 5,5 0,0 0,0 5,2.5 5.0001,5 5)))')).wkt,
+            'POLYGON EMPTY',
+        )
+        self.assertEqual(
+            boundary.simple_shape.ogr.difference(OGRGeometry('MULTIPOLYGON (((5 5,5 0,0 0,0 5,5 5)))')).wkt,
+            'POLYGON EMPTY',
+        )
diff --git a/boundaries/tests/test_geometry.py b/boundaries/tests/test_geometry.py
index 6c4e671..a4942e2 100644
--- a/boundaries/tests/test_geometry.py
+++ b/boundaries/tests/test_geometry.py
@@ -44,7 +44,10 @@ def test_unary_union(self):
         geometry = Geometry(OGRGeometry('MULTIPOLYGON (((0 0,0 5,5 5,0 0)),((0 0,5 0,5 5,0 0)))')).unary_union()
         self.assertIsInstance(geometry, Geometry)
         self.assertEqual(geometry.geometry.geom_name, 'MULTIPOLYGON')
-        self.assertEqual(geometry.wkt, 'MULTIPOLYGON (((0 0,0 5,5 5,5 0,0 0)))')
+        self.assertEqual(
+            geometry.geometry.difference(OGRGeometry('MULTIPOLYGON (((0 0,0 5,5 5,5 0,0 0)))')).wkt,
+            'POLYGON EMPTY',
+        )
 
     def test_merge_with_ogrgeometry(self):
         other = OGRGeometry('MULTIPOLYGON (((5 0,5 3,2 0,5 0)))')
diff --git a/boundaries/tests/test_loadshapefiles.py b/boundaries/tests/test_loadshapefiles.py
index 9cf508c..44a3397 100644
--- a/boundaries/tests/test_loadshapefiles.py
+++ b/boundaries/tests/test_loadshapefiles.py
@@ -5,6 +5,7 @@
 from datetime import date
 from zipfile import BadZipfile
 
+from django.contrib.gis.gdal import OGRGeometry
 from django.core.management import call_command
 from django.test import TestCase
 from testfixtures import LogCapture
@@ -196,12 +197,9 @@ def test_union_merge_strategy(self):
         Command().load_boundary(self.feature, 'invalid')
 
         boundary = Command().load_boundary(self.feature, 'union')
-        try:  # Django < 2.2
-            self.assertEqual(boundary.shape.ogr.wkt, 'MULTIPOLYGON (((0.0001 0.0001,0 5,0 5,0 5,5 5,5 5,0.0001 0.0001)))')
-            self.assertEqual(boundary.simple_shape.ogr.wkt, 'MULTIPOLYGON (((0.0001 0.0001,0 5,5 5,5 5,0.0001 0.0001)))')
-        except AssertionError:
-            self.assertEqual(boundary.shape.ogr.wkt, 'MULTIPOLYGON (((0.0001 0.0001,0 5,5 5,0.0001 0.0001)))')
-            self.assertEqual(boundary.simple_shape.ogr.wkt, 'MULTIPOLYGON (((0.0001 0.0001,0 5,5 5,0.0001 0.0001)))')
+        expected = OGRGeometry('MULTIPOLYGON (((0.0001 0.0001,0 5,5 5,0.0001 0.0001)))')
+        self.assertEqual(boundary.shape.ogr.difference(expected).wkt, 'POLYGON EMPTY')
+        self.assertEqual(boundary.simple_shape.ogr.difference(expected).wkt, 'POLYGON EMPTY')
         self.assertRegex(boundary.centroid.ogr.wkt, r'\APOINT \(1\.6667 3\.3333666666666+7\)\Z')
         self.assertEqual(boundary.extent, (0.0, 0.0001, 5.0, 5.0))