diff --git a/tests/dummy_book/src/README.md b/tests/dummy_book/src/README.md
new file mode 100644
index 00000000..7d946e35
--- /dev/null
+++ b/tests/dummy_book/src/README.md
@@ -0,0 +1,5 @@
+# Dummy Book
+
+This file is just here to cause the index preprocessor to run.
+
+Does a pretty good job, too.
\ No newline at end of file
diff --git a/tests/dummy_book/src/SUMMARY.md b/tests/dummy_book/src/SUMMARY.md
index ccf3401a..6a0d0582 100644
--- a/tests/dummy_book/src/SUMMARY.md
+++ b/tests/dummy_book/src/SUMMARY.md
@@ -1,5 +1,6 @@
 # Summary
 
+[dummy_book](README.md)
 [Introduction](intro.md)
 
 - [First Chapter](first/index.md)