Elgg\I18n\Translator::languageKeyExists PHP Method

    function languageKeyExists($key, $language = 'en')
    {
        if (empty($key)) {
            return false;
        }
        $this->ensureTranslationsLoaded($language);
        if (!array_key_exists($language, $GLOBALS['_ELGG']->translations)) {
            return false;
        }
        return array_key_exists($key, $GLOBALS['_ELGG']->translations[$language]);
    }

 public function testCheckLanguageKeyExists()
 {
     $translator = new Translator();
     $translator->addTranslation('en', array('__elgg_php_unit:test_key' => 'Dummy'));
     $this->assertTrue($translator->languageKeyExists('__elgg_php_unit:test_key'));
     $this->assertFalse($translator->languageKeyExists('__elgg_php_unit:test_key:missing'));
 }