diff --git a/highlighters/main/test-data/history-expansion.zsh b/highlighters/main/test-data/history-expansion.zsh
index c670312..0e1c4a6 100644
--- a/highlighters/main/test-data/history-expansion.zsh
+++ b/highlighters/main/test-data/history-expansion.zsh
@@ -27,6 +27,7 @@
 # vim: ft=zsh sw=2 ts=2 et
 # -------------------------------------------------------------------------------------------------
 
+ZSH_HIGHLIGHT_STYLES[default]=$unused_highlight
 BUFFER='!foo bar !baz'
 
 expected_region_highlight=(