functests: Fix tests

test/functional/api/window_spec.lua

@@ -9,6 +9,7 @@ local funcs = helpers.funcs
 local request = helpers.request
 local NIL = helpers.NIL
 local meth_pcall = helpers.meth_pcall
+local meths = helpers.meths
 local command = helpers.command
 
 -- check if str is visible at the beginning of some line
@@ -55,6 +56,12 @@ describe('api/win', function()
       eq('typing\n  some dumb text', curbuf_contents())
     end)
 
+    it('does not leak memory when using invalid window ID with invalid pos',
+    function()
+      eq({false, 'Invalid window id'},
+         meth_pcall(meths.win_set_cursor, 1, {"b\na"}))
+    end)
+
     it('updates the screen, and also when the window is unfocused', function()
       insert("prologue")
       feed('100o<esc>')