constness fixes, round-trip and fuzz-testing for CHOICE
diff --git a/tests/tests-randomized/bundles/00-NULL-bundle.txt b/tests/tests-randomized/bundles/00-NULL-bundle.txt
new file mode 100644
index 0000000..7951def
--- /dev/null
+++ b/tests/tests-randomized/bundles/00-NULL-bundle.txt
@@ -0,0 +1 @@
+NULL