--- libzeitgeist-0.3.18/tests/test-datasource.c.env	2012-04-05 19:05:20.000000000 +0900
+++ libzeitgeist-0.3.18/tests/test-datasource.c	2014-06-09 22:27:26.000000000 +0900
@@ -48,7 +48,10 @@ setup (Fixture *fix, gconstpointer data)
 static void
 teardown (Fixture *fix, gconstpointer data)
 {
-  g_setenv ("XDG_DATA_DIRS", old_xdg_data_dirs, TRUE);  
+  if (old_xdg_data_dirs)
+    g_setenv ("XDG_DATA_DIRS", old_xdg_data_dirs, TRUE);  
+  else
+    g_unsetenv("XDG_DATA_DIRS");
 }
 
 static void
--- libzeitgeist-0.3.18/tests/test-event.c.env	2012-04-05 19:05:20.000000000 +0900
+++ libzeitgeist-0.3.18/tests/test-event.c	2014-06-09 22:25:37.000000000 +0900
@@ -47,7 +47,10 @@ setup (Fixture *fix, gconstpointer data)
 static void
 teardown (Fixture *fix, gconstpointer data)
 {
-  g_setenv ("XDG_DATA_DIRS", old_xdg_data_dirs, TRUE);  
+  if (old_xdg_data_dirs)
+    g_setenv ("XDG_DATA_DIRS", old_xdg_data_dirs, TRUE);  
+  else
+    g_unsetenv("XDG_DATA_DIRS");
 }
 
 static void