diff --git a/Makefile b/Makefile
index 6154e1d8363343e12153e52a27e9826581afdc3a..e3227843ac85068c685009b7f1d7eacf39d5a316 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,8 @@ all: pdf
 test: pdf
 	LD_LIBRARY_PATH=$(HAMMER_LIB) sh -c \
 	'for x in t/*.pdf; do ./pdf "$$x" >/dev/null && echo OK: "$$x"; done'
+	LD_LIBRARY_PATH=$(HAMMER_LIB) sh -c \
+	'for x in t/should_fail/*.pdf; do ./pdf "$$x" >/dev/null ; done'
 	@true
 
 pdf: $(SOURCES)