mocked modules are not returned to normal state when verify/1 returns #8
Description
Sometime after the switch to gen_statem (it may be completelely unconnected to that change) I regularly get errors like the one below.
When inserting a timer:sleep(100) after the em:verify/1 in the previous test of my eunit suite all works fine. I have started to add a sleep after every verify to work around this.
I have had a look at the code, but cannot find a race condition (at least no according to the documentation of the Erlang API functions that are called by erlymock)
=ERROR REPORT==== 29-Nov-2017::18:23:46 ===
** State machine <0.4811.0> terminating
** Last event = {{call,{<0.4809.0>,#Ref<0.4180725794.4003201027.186836>}},
{replay,infinity}}
** When server state = {programming,
{state,<0.4809.0>,infinity,
[{expectation,#Ref<0.4180725794.4003201027.186833>,
{root,#Ref<0.4180725794.4003201027.186829>},
quperl_client_event_mgr,new_object,
[<<1,2,3,4>>],
{return,ok},
[]},
{expectation,#Ref<0.4180725794.4003201027.186831>,
{root,#Ref<0.4180725794.4003201027.186829>},
quperl_client_cache,create_object,
[<<1,2,3,4>>,[{name,"foo"}]],
{return,ok},
[]}],
[],
[{expectation,#Ref<0.4180725794.4003201027.186835>,
{root,#Ref<0.4180725794.4003201027.186829>},
quperl_client_event_mgr,fail,
[#Fun<quperl_client_util.is_object_id.1>,
txn_mgr_terminated],
{return,ok},
[]}],
[],[],[],undefined,no_error}}
** Reason for termination = error:{bad_return_from_state_function,
{em_error_module_already_mocked,
quperl_client_event_mgr}}
** Callback mode = state_functions
** Stacktrace =
** [{gen_statem,parse_event_result,8,[{file,"gen_statem.erl"},{line,1318}]},
{gen_statem,loop_event,6,[{file,"gen_statem.erl"},{line,1015}]},
{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,247}]}]