I would like to be able to progressively set up a mock (using Meck), so that expectations for different calls are set in different test setup functions. I thought merge_expects
might do the trick. But I am seeing unexpected results:
default__second_expect_overwrites_first_expect_test() ->
meck:unload(),
meck:new(womble, [non_strict]),
meck:expect(womble, sleep, fun(8) -> ok end),
meck:expect(womble, sleep, fun(24) -> comatose end),
?assertEqual(comatose, womble:sleep(24)),
?assertError(function_clause, womble:sleep(8)).
merge_expects__second_expect_has_no_effect_test() ->
meck:unload(),
meck:new(womble, [non_strict, merge_expects]),
meck:expect(womble, sleep, fun(8) -> ok end),
meck:expect(womble, sleep, fun(24) -> comatose end),
?assertError(function_clause, womble:sleep(24)),
?assertEqual(ok, womble:sleep(8)).
I know that I can use the following workaround, but it will uglify my tests:
workaround_test() ->
meck:unload(),
meck:new(womble, [non_strict]),
meck:expect(womble, sleep, [{[8], ok}, {[24], comatose}]),
?assertEqual(comatose, womble:sleep(24)),
?assertEqual(ok, womble:sleep(8)).
This seems to be a "bug" related to using funs as expectations specifications (I think it was never supported in the first place, but in any case it is not documented clearly). As a workaround, you could use expect/4
:
1> meck:new(womble, [non_strict, no_link, merge_expects]).
ok
2> meck:expect(womble, sleep, [24], comatose).
ok
3> womble:sleep(8).
** exception error: no function clause matching womble:sleep(8)
4> womble:sleep(24).
comatose
5> meck:expect(womble, sleep, [8], ok).
ok
6> womble:sleep(8).
ok
7> womble:sleep(24).
comatose