diff --git a/ports/unix/variants/coverage/frzmpy/frzqstr.py b/ports/unix/variants/coverage/frzmpy/frzqstr.py
new file mode 100644
index 0000000000..051f2a9c16
--- /dev/null
+++ b/ports/unix/variants/coverage/frzmpy/frzqstr.py
@@ -0,0 +1,3 @@
+# Checks for regression on MP_QSTR_NULL
+def returns_NULL():
+    return "NULL"