Getting terminal width from within an ExUnit Formatter

I get this just fine. Are you ‘sure’ your output is a proper terminal stream? What is it precisely?

Had my question answered elsewhere, by José.

Basically the issue is that its not a terminal if it isn’t running inside an iex session.

$> elixir -e "IO.inspect :io.columns"
{:error, :enotsup}

$> iex -e "IO.inspect :io.columns"
Erlang/OTP 21 [erts-10.3.4] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]

{:ok, 238}

So for anyone else writing an ExUnit formatter or anything else that needs to get the column count, you have to run within IEx, or manually specify the tty device you’re targeting.

Ah that’s correct yeah, didn’t know you were running it not in iex. Erlang needs a shell running to pull that information.