diff --git a/kitty_tests/keys.py b/kitty_tests/keys.py
index 6571d7648..cbc044ab7 100644
--- a/kitty_tests/keys.py
+++ b/kitty_tests/keys.py
@@ -396,6 +396,7 @@ class TestKeys(BaseTest):
         ae(enc(key=ord(' '), mods=ctrl), '\0')
         ae(enc(key=ord('i'), mods=ctrl | shift), csi(ctrl | shift, ord('i')))
         ae(enc(key=defines.GLFW_FKEY_LEFT_SHIFT), '')
+        ae(enc(key=defines.GLFW_FKEY_CAPS_LOCK), '')
 
         q = partial(enc, key=ord('a'))
         ae(q(), 'a')