diff --git a/tests/core/test_theme.py b/tests/core/test_theme.py
index 46f91d2..1865992 100644
--- a/tests/core/test_theme.py
+++ b/tests/core/test_theme.py
@@ -85,21 +85,26 @@ class theme(unittest.TestCase):
 
     def test_wal_colors(self):
         with unittest.mock.patch('core.theme.io') as io:
-            io.open.return_value.__enter__.return_value.read.return_value='''
-                { "colors": { "red": "#ff0000" } }
-            '''
+            with unittest.mock.patch('core.theme.os') as os:
+                os.path.isfile.return_value = True
+                io.open.return_value = unittest.mock.MagicMock()
+                io.open.return_value.__enter__.return_value.read.return_value='''
+                    { "colors": { "red": "#ff0000" } }
+                '''
 
-            theme = core.theme.Theme(raw_data=self.walTheme)
-            self.assertEqual({'red': '#ff0000'}, theme.keywords())
+                theme = core.theme.Theme(raw_data=self.walTheme)
+                self.assertEqual({'red': '#ff0000'}, theme.keywords())
 
     def test_wal_special(self):
         with unittest.mock.patch('core.theme.io') as io:
-            io.open.return_value.__enter__.return_value.read.return_value='''
-                { "special": { "background": "#ff0000" } }
-            '''
+            with unittest.mock.patch('core.theme.os') as os:
+                os.path.isfile.return_value = True
+                io.open.return_value.__enter__.return_value.read.return_value='''
+                    { "special": { "background": "#ff0000" } }
+                '''
 
-            theme = core.theme.Theme(raw_data=self.walTheme)
-            self.assertEqual({'background': '#ff0000'}, theme.keywords())
+                theme = core.theme.Theme(raw_data=self.walTheme)
+                self.assertEqual({'background': '#ff0000'}, theme.keywords())
 
     def test_cycle_value(self):
         widget = core.widget.Widget()