public function testFixLetterCase()
 {
     $tests = array('tst' => 'test', 'Tst' => 'Test', 'TST' => 'TEST', 'tSt' => null);
     foreach ($tests as $case => $expect) {
         foreach (array('test', 'TEST') as $string) {
             $result = ArcanistSpellingLinter::fixLetterCase($string, $case);
             $this->assertEqual($expect, $result, $case);
         }
     }
 }