Tests JavaScript files that have querystrings attached get added right.
function testAddJsFileWithQueryString() {
  $this
    ->drupalGet('common-test/query-string');
  $query_string = variable_get('css_js_query_string', '0');
  $this
    ->assertRaw(drupal_get_path('module', 'node') . '/node.js?' . $query_string, 'Query string was appended correctly to js.');
}