diff --git a/Makefile.am b/Makefile.am
index 4a474e095..5ffe5aac6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -31,6 +31,7 @@ _DISABLEDSRCS += tests/variations-%
 endif
 export DISABLEDSRCS ?= $(filter $(_DISABLEDSRCS),$(_TESTSRCS))
 TESTSRCS ?= $(filter-out $(DISABLEDSRCS),$(_TESTSRCS))
+TESTPREVIEWS ?= $(addsuffix .pdf,$(basename $(filter-out $(_DISABLEDSRCS),$(_TESTPREVIEWS))))
 
 # Since we can't use $(wildcard ...) in automake file lists, we generate a file
 # with a script that builds our dynamic file lists instead. This is tricky,
diff --git a/build-aux/list-dist-files.sh.in b/build-aux/list-dist-files.sh.in
index f47bf26a0..aebcb9c7f 100755
--- a/build-aux/list-dist-files.sh.in
+++ b/build-aux/list-dist-files.sh.in
@@ -22,7 +22,7 @@ finder tests -maxdepth 1 -name '*.xml'
 finder tests -maxdepth 1 -name '*.lua'
 finder tests -maxdepth 1 -name '*.nil'
 
-printf '\n%s' "TESTPREVIEWS ?="
+printf '\n%s' "_TESTPREVIEWS ?="
 {
 finder tests -maxdepth 1 -name '*.sil'
 finder tests -maxdepth 1 -name '*.xml'
@@ -30,7 +30,6 @@ finder tests -maxdepth 1 -name '*.lua'
 finder tests -maxdepth 1 -name '*.nil'
 } |
     xargs @GREP@ -L KNOWNBAD |
-    @SED@ 's/\....$/.pdf/' |
     xargs printf ' %s'
 
 printf '\n%s' "BUSTEDSPECS ?="