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W0022 - Missing no_link option in meck:new invocation

Error​

   -module(my_SUITE).

   -export([all/0, init_per_suite/1]).
   -export([a/1]).

   all() -> [a].

   init_per_suite(Config) ->
     meck:new(my_module, [passthrough]),
  %% ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 warning: Missing no_link option.
     Config.

   a(_Config) ->
     ok.

Explanation​

In Common Test, every test case is executed by a dedicated Erlang process. The init_per_suite/1 and init_per_group/2 configuration functions are executed in separate processes. Every linked process spawned in those functions will be killed once the function stops executing.

Unless the no_link option is passed to the meck:new/1,2 invocations, the spawned process is linked, so the mock would stop working before (or while) a testcase is executing, often leading to flakyness.

To fix this issue, pass the no_link option to the meck:new/1,2 invocation or activate the mock outside of the init_per_suite/1 and init_per_group/2 functions.

For more information, please refer to the official documentation.