diff --git a/plugins/hls-change-type-signature-plugin/hls-change-type-signature-plugin.cabal b/plugins/hls-change-type-signature-plugin/hls-change-type-signature-plugin.cabal
index 0ddf137da8..7a1e9c20bb 100644
--- a/plugins/hls-change-type-signature-plugin/hls-change-type-signature-plugin.cabal
+++ b/plugins/hls-change-type-signature-plugin/hls-change-type-signature-plugin.cabal
@@ -15,6 +15,7 @@ extra-source-files:
   LICENSE
   README.md
   test/testdata/*.hs
+  test/testdata/*.txt
   test/testdata/*.yaml
 
 library