PhpSpec\Formatter\Presenter\Differ\Differ::compare PHP Method

    public function compare($expected, $actual)
    {
        foreach ($this->engines as $engine) {
            if ($engine->supports($expected, $actual)) {
                return rtrim($engine->compare($expected, $actual));
            }
        }
    }

 /**
  * @param array $actualArguments
  * @param array $expectedArguments
  *
  * @return string
  */
 private function generateArgumentsDifferenceText(array $actualArguments, array $expectedArguments)
 {
     $text = '';
     foreach ($actualArguments as $i => $actualArgument) {
         $expectedArgument = $expectedArguments[$i];
         $actualArgument = is_null($actualArgument) ? 'null' : $actualArgument;
         $expectedArgument = is_null($expectedArgument) ? 'null' : $expectedArgument;
         $text .= $this->differ->compare($expectedArgument, $actualArgument);
     }
     return $text;
 }