diff --git a/_test_data/sandbox/clean/base.txt b/_test_data/sandbox/clean/base.txt
new file mode 100644
index 0000000..3b5599a
--- /dev/null
+++ b/_test_data/sandbox/clean/base.txt
@@ -0,0 +1,2 @@
+clean stack: base branch
+purpose: baseline parent PR