Fix order of args in TestDriver.

Author: crertel

lib/scenic/driver.ex

@@ -348,7 +348,7 @@ defmodule Scenic.Driver do
   This callback is optional.
   """
   @callback take_screenshot(driver :: Driver.t()) ::
-              {:ok, :not_supported} | {:ok, screenshot_t, Driver.t()}
+              {:ok, :not_supported, Driver.t()} | {:ok, screenshot_t, Driver.t()}
 
   @optional_callbacks reset_scene: 1,
                       request_input: 2,

test/scenic/view_port_test.exs

@@ -83,7 +83,7 @@ defmodule Scenic.ViewPortTest do
     def request_input(_input, driver), do: {:ok, driver}
     def reset_scene(driver), do: {:ok, driver}
     def clear_color(_color, driver), do: {:ok, driver}
-    def take_screenshot(driver), do: {:ok, driver, {1, 1, :rgba, <<0x00, 0x00, 0x00, 0xFF>>}}
+    def take_screenshot(driver), do: {:ok, {1, 1, :rgba, <<0x00, 0x00, 0x00, 0xFF>>}, driver}
 
     def handle_info(_, driver), do: {:noreply, driver}
     def handle_cast(_, driver), do: {:noreply, driver}