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** (DBConnection.Error) owner #PID<> exited while testing async function
I need some help to understand writing test for async function
For example I have a function
def send_notification({:ok, nessage}, to, title, body) do
Task.Supervisor.async_nolink(MyApp.TaskSupervisor, fn ->
send(to, title, body)
end)
end
def create(to, title, body) do
to
|> create_message(title, body)
|> send(to, title, body)
|> log_message()
end
If I run test for create function, I got an error
13:19:41.877 [error] Postgrex.Protocol (#PID<0.1313.0>) disconnected: ** (DBConnection.ConnectionError) owner #PID<0.4033.0> exited
Client #PID<0.4035.0> is still using a connection from owner at location:
:prim_inet.recv0/3
(postgrex 0.16.5) lib/postgrex/protocol.ex:3171: Postgrex.Protocol.msg_recv/4
(postgrex 0.16.5) lib/postgrex/protocol.ex:2871: Postgrex.Protocol.recv_transaction/4
(postgrex 0.16.5) lib/postgrex/protocol.ex:2180: Postgrex.Protocol.rebind_execute/4
(ecto_sql 3.9.1) lib/ecto/adapters/sql/sandbox.ex:375: Ecto.Adapters.SQL.Sandbox.Connection.proxy/3
(db_connection 2.4.3) lib/db_connection/holder.ex:354: DBConnection.Holder.holder_apply/4
(db_connection 2.4.3) lib/db_connection.ex:1413: DBConnection.run_execute/5
(db_connection 2.4.3) lib/db_connection.ex:1508: DBConnection.run/6
(db_connection 2.4.3) lib/db_connection.ex:701: DBConnection.execute/4
(ecto_sql 3.9.1) lib/ecto/adapters/postgres/connection.ex:102: Ecto.Adapters.Postgres.Connection.execute/4
(ecto_sql 3.9.1) lib/ecto/adapters/sql.ex:858: Ecto.Adapters.SQL.execute!/5
(ecto_sql 3.9.1) lib/ecto/adapters/sql.ex:828: Ecto.Adapters.SQL.execute/6
(ecto 3.9.4) lib/ecto/repo/queryable.ex:229: Ecto.Repo.Queryable.execute/4
(ecto 3.9.4) lib/ecto/repo/queryable.ex:19: Ecto.Repo.Queryable.all/3
(ecto 3.9.4) lib/ecto/repo/preloader.ex:272: Ecto.Repo.Preloader.fetch_query/8
(elixir 1.14.2) lib/enum.ex:1658: Enum."-map/2-lists^map/1-0-"/2
(ecto 3.9.4) lib/ecto/repo/preloader.ex:72: Ecto.Repo.Preloader.preload_each/4
(ecto 3.9.4) lib/ecto/repo/preloader.ex:51: Ecto.Repo.Preloader.normalize_and_preload_each/5
(ecto 3.9.4) lib/ecto/repo/preloader.ex:46: Ecto.Repo.Preloader.preload/4
And I read the doc But I can’t figure out how to write test for this async function
And sandbox is :manual mode
Ecto.Adapters.SQL.Sandbox.mode(MyAppRepo, :manual)
Most Liked
josevalim
Nowadays we have proper abstractions in place so this doesn’t happen as often.
First, for managing connections, make sure you are using the start_owner API: todo_trek/test/support/data_case.ex at main · chrismccord/todo_trek · GitHub
When you are starting processes under test, use start_supervisor! from ExUnit, which guarantees it will be shut down before the test process.
Finally, if you are starting tasks or processes under a supervisor dynamically, add an on_exit callback that gets all children of said supervisor and wait for them to terminate. Something like:
on_exit(fn ->
for {_, pid, _, _} <- DynamicSupervisor.which_children(YourSupName) do
ref = Process.monitor(pid)
assert_receive {:DOWN, ^ref, _, _, _}, :infinity
end
end)
Joep
When searching for start_supervisor! in the docs I get no results: Search — ExUnit v1.16.0!
Sorry, we couldn’t find anything for start_supervisor!.
I suppose you mean start_supervised!/2 ?
dimitarvp
Yep, that’s the one.
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