Merge #6539 'More cursor shape modes'

test/functional/helpers.lua

@@ -392,7 +392,14 @@ end
 
 -- sleeps the test runner (_not_ the nvim instance)
 local function sleep(ms)
-  run(nil, nil, nil, ms)
+  local function notification_cb(method, _)
+    if method == "redraw" then
+      error("Screen is attached; use screen:sleep() instead.")
+    end
+    return true
+  end
+
+  run(nil, notification_cb, nil, ms)
 end
 
 local function curbuf_contents()