Index: tests/destroy.test
===================================================================
diff -u -N -reae784ccc80b2a18b83fbe631c32d549189f7927 -rb053832535f9d1903fc0c0c3cb3523653bd63dfe
--- tests/destroy.test	(.../destroy.test)	(revision eae784ccc80b2a18b83fbe631c32d549189f7927)
+++ tests/destroy.test	(.../destroy.test)	(revision b053832535f9d1903fc0c0c3cb3523653bd63dfe)
@@ -616,6 +616,7 @@
   ::module destroy
 }
 
+
 # to avoid CallDirectly, we could activate this line
 ::nx::Class create M {:method dealloc args {next}}
 Test case delete-parent-namespace-dealloc
@@ -972,4 +973,23 @@
   # We expect that the original method works again.
   #
   ? {string match ::nsf::__#* [A new]} 1
-}
\ No newline at end of file
+}
+
+#
+# Create a cyclical class dependency and delete it manually
+#
+nx::Test case cyclical-dependency {
+  nx::Object create o1
+  ? {nx::Class create o1::C} ::o1::C
+  ? {nsf::relation o1 class o1::C} ::o1::C
+  o1 destroy
+}
+
+#
+# Create a cyclical class dependency and let it be deleted on
+# object-system-cleanup
+#
+nx::Object create o1
+nx::Class create o1::C
+nsf::relation o1 class o1::C
+