/**
  * Test elixir method.
  *
  * @return void
  */
 public function testElixir()
 {
     global $env;
     $res = new Resource();
     // External URL's
     $url = 'https://www.google.com/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png';
     $this->assertEquals($res->elixir($url), $url);
     $asset = 'style.css';
     $this->assertEquals('/asset/' . $asset, $res->elixir($asset));
     $env['APP_ASSET_SOURCE'] = 'build';
     $this->assertEquals('/build/style.123456.css', $res->elixir($asset));
     $asset = 'logo.png';
     file_put_contents(__DIR__ . '/temp/' . $asset, '');
     $this->assertEquals($asset, $res->elixir($asset));
     unlink(__DIR__ . '/temp/' . $asset);
     file_put_contents(__DIR__ . '/temp/assets/' . $asset, '');
     $this->assertEquals('/assets/' . $asset, $res->elixir($asset));
     unlink(__DIR__ . '/temp/assets/' . $asset);
     $asset = 'logo1.png';
     $this->assertEquals('', $res->elixir($asset));
 }