Fixes bug in IEx.Config.configuration

IEx.Config.configuration was raising a FunctionClauseError since
it did not have a default value for width

Signed-off-by: José Valim <[email protected]>

Author: tokafish

lib/iex/lib/iex/config.ex

@@ -63,6 +63,7 @@ defmodule IEx.Config do
   defp default_option(:colors), do: [{:enabled, IO.ANSI.enabled?} | default_colors()]
   defp default_option(:inspect), do: []
   defp default_option(:history_size), do: 20
+  defp default_option(:width), do: width()
 
   defp default_option(prompt) when prompt in [:default_prompt, :alive_prompt] do
     "%prefix(%counter)>"

lib/iex/test/iex/config_test.exs

@@ -0,0 +1,9 @@
+Code.require_file "../test_helper.exs", __DIR__
+
+defmodule IEx.ConfigTest do
+  use ExUnit.Case, async: true
+
+  test "configuration sets a default for width" do
+    assert IEx.Config.configuration[:width] == 80
+  end
+end