public function testStem()
 {
     $input_handle = fopen('./resources/words/input.txt', 'r');
     $output_handle = fopen('./resources/words/output.txt', 'r');
     while ($in_word = trim(fgets($input_handle))) {
         $out_word = trim(fgets($output_handle));
         $this->assertEquals($out_word, fGrammar::stem($in_word));
     }
 }