diff --git a/unit_tests/__init__.py b/unit_tests/__init__.py
index 973e4e6d..57f6ad24 100644
--- a/unit_tests/__init__.py
+++ b/unit_tests/__init__.py
@@ -1,6 +1,7 @@
 import os
 import sys
 
+from unittest.mock import patch
 
 _path = os.path.dirname(os.path.realpath(__file__))
 _hooks = os.path.abspath(os.path.join(_path, '../hooks'))
@@ -16,3 +17,15 @@ def _add_path(path):
 _add_path(_hooks)
 _add_path(_actions)
 _add_path(_unit_tests)
+
+# Patch out lsb_release() and get_platform() as unit tests should be fully
+# insulated from the underlying platform.  Unit tests assume that the system is
+# ubuntu jammy.
+patch(
+    'charmhelpers.osplatform.get_platform', return_value='ubuntu'
+).start()
+patch(
+    'charmhelpers.core.host.lsb_release',
+    return_value={
+        'DISTRIB_CODENAME': 'jammy'
+    }).start()