Merge pull request #3025 from MSch/flush-logger-after-tests

Call Logger.flush in System.at_exit when running mix test.

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

Author: josevalim

lib/mix/lib/mix/tasks/test.ex

@@ -190,6 +190,13 @@ defmodule Mix.Tasks.Test do
     if cover, do: cover.()
 
     System.at_exit fn _ ->
+      # Make sure all messages the tests might have sent to the
+      # Logger are printed before we shut down the VM.
+      case Process.whereis(Logger) do
+        pid when is_pid(pid) -> Logger.flush()
+        nil -> :ok
+      end
+
       if failures > 0, do: exit({:shutdown, 1})
     end
   end