1 files changed, 6 insertions, 3 deletions

diff --git a/tests/lanes_as_upvalue.lua b/tests/lanes_as_upvalue.lua
index 7cc5e14..c1944b0 100644
--- a/tests/lanes_as_upvalue.lua
+++ b/tests/lanes_as_upvalue.lua
@@ -1,8 +1,11 @@
-local lanes = require "lanes".configure() -- with timers enabled
+local lanes = require "lanes".configure{ verbose_errors = true} -- with timers enabled
 
 local function foo()
         local lanes = lanes -- lanes as upvalue
 end
 
-local h = lanes.gen( "*", foo)()
-h:join()
+local g = lanes.gen( "*", foo)
+
+-- this should raise an error as lanes.timer_lane is a Lane (a non-deep full userdata)
+local res, err = pcall( g)
+print( "Generating lane yielded: ", tostring( res), tostring( err))