diff --git a/src/testdir/samples/test_undo.txt b/src/testdir/samples/test_undo.txt
new file mode 100644
index 0000000..4cb29ea
--- /dev/null
+++ b/src/testdir/samples/test_undo.txt
@@ -0,0 +1,3 @@
+one
+two
+three
diff --git a/src/testdir/samples/test_undo.txt.undo b/src/testdir/samples/test_undo.txt.undo
new file mode 100644
index 0000000..393af7f
--- /dev/null
+++ b/src/testdir/samples/test_undo.txt.undo
Binary files differ