diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 68dbb0a..1a05a59 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2681,6 +2681,7 @@
     endif
     call assert_fails('call term_start("' .. cmd .. '", #{term_finish: "close"'
         \ .. ', ansi_colors: range(16)})', 'E475:')
+    unlet g:terminal_ansi_colors
   endif
 
   " type()