diff --git a/_test_data/sandbox/clean/child.txt b/_test_data/sandbox/clean/child.txt
new file mode 100644
index 0000000..276890d
--- /dev/null
+++ b/_test_data/sandbox/clean/child.txt
@@ -0,0 +1,2 @@
+clean stack: child branch
+purpose: child PR on top of sandbox-clean-base