diff --git a/src/testdir/test_python3.vim b/src/testdir/test_python3.vim
index b216877..95d49db 100644
--- a/src/testdir/test_python3.vim
+++ b/src/testdir/test_python3.vim
@@ -605,7 +605,7 @@
   py3 d = vim.bindeval('d')
   call assert_equal(2, py3eval('len(d)'))
 
-  " Deleting an non-existing key
+  " Deleting a non-existing key
   call AssertException(["py3 del d['c']"], "Vim(py3):KeyError: 'c'")
 endfunc