diff --git a/include-files/Makefile b/include-files/Makefile
index c5f5279e..0e060f86 100644
--- a/include-files/Makefile
+++ b/include-files/Makefile
@@ -10,6 +10,6 @@ expected.native: sample.md file-a.md file-b.md file-c.md include-files.lua
 	pandoc --lua-filter=include-files.lua --output $@ $<
 
 expected-auto.native: sample.md file-a.md file-b.md file-c.md include-files.lua
-	pandoc --lua-filter=include-files.lua --output $@ $<
+	pandoc --lua-filter=include-files.lua -M include-auto --output $@ $<
 
 .PHONY: test