/**
 * Get installed translations.
 *
 * Looks in the wp-content/languages directory for translations of
 * plugins or themes.
 *
 * @since 3.7.0
 *
 * @param string $type What to search for. Accepts 'plugins', 'themes', 'core'.
 * @return array Array of language data.
 */
function wp_get_installed_translations($type)
{
    if ($type !== 'themes' && $type !== 'plugins' && $type !== 'core') {
        return array();
    }
    $dir = 'core' === $type ? '' : "/{$type}";
    if (!is_dir(WP_LANG_DIR)) {
        return array();
    }
    if ($dir && !is_dir(WP_LANG_DIR . $dir)) {
        return array();
    }
    $files = scandir(WP_LANG_DIR . $dir);
    if (!$files) {
        return array();
    }
    $language_data = array();
    foreach ($files as $file) {
        if ('.' === $file[0] || is_dir(WP_LANG_DIR . "{$dir}/{$file}")) {
            continue;
        }
        if (substr($file, -3) !== '.po') {
            continue;
        }
        if (!preg_match('/(?:(.+)-)?([a-z]{2,3}(?:_[A-Z]{2})?(?:_[a-z0-9]+)?).po/', $file, $match)) {
            continue;
        }
        if (!in_array(substr($file, 0, -3) . '.mo', $files)) {
            continue;
        }
        list(, $textdomain, $language) = $match;
        if ('' === $textdomain) {
            $textdomain = 'default';
        }
        $language_data[$textdomain][$language] = wp_get_pomo_file_data(WP_LANG_DIR . "{$dir}/{$file}");
    }
    return $language_data;
}

 /**
  * @ticket 35284
  */
 function test_wp_get_pomo_file_data()
 {
     $file = DIR_TESTDATA . '/pomo/empty.po';
     $array = wp_get_pomo_file_data($file);
     $this->assertArrayHasKey('POT-Creation-Date', $array);
     $this->assertArrayHasKey('PO-Revision-Date', $array);
     $this->assertArrayHasKey('Project-Id-Version', $array);
     $this->assertArrayHasKey('X-Generator', $array);
     $file = DIR_TESTDATA . '/pomo/mo.pot';
     $array = wp_get_pomo_file_data($file);
     $this->assertNotEmpty($array['POT-Creation-Date']);
     $this->assertNotEmpty($array['PO-Revision-Date']);
     $this->assertNotEmpty($array['Project-Id-Version']);
     $this->assertArrayHasKey('X-Generator', $array);
     $file = DIR_TESTDATA . '/languages/es_ES.po';
     $array = wp_get_pomo_file_data($file);
     $this->assertArrayHasKey('POT-Creation-Date', $array);
     $this->assertNotEmpty($array['PO-Revision-Date']);
     $this->assertNotEmpty($array['Project-Id-Version']);
     $this->assertNotEmpty($array['X-Generator']);
 }