Run Elixir's 'mix test' in a loop, triggered by file changes.

mix_test_loop.fish

function mix_test_loop --description "Run 'mix test' in a loop, triggered by file changes"
  # file: ~/.config/fish/functions/mix_test_loop.fish
  #
  # Run 'mix test' in a loop.  We'll only update the screen when an elixir file
  # changes.
  #
  # usage: mix_test_loop 5
  #
  # Where the second argument is the number of seconds to wait
  # before starting the loop again.  Defaults to 5 seconds.
  #
  function _files_mtime
    echo (stat --printf '{%n, %Y}' (find -regex '.+\.ex[s]*$'))
  end

  # Set a sleep default
  if test -n "$argv"
    set -g mix_test_loop_sleep $argv
  else
    set -g mix_test_loop_sleep 5
  end

  # Start the main loop
  while true
    if test -n (echo $mix_test_loop_files)
      if test $mix_test_loop_files != (_files_mtime)
        clear
        mix test
        set -g mix_test_loop_files (_files_mtime)
      end
    else
      set -g mix_test_loop_files (_files_mtime)
      clear
      mix test
    end
    sleep (echo $mix_test_loop_sleep)
  end
    
end