Tests that CssCommand objects can be constructed and rendered.
function testCssCommand() {
  $command = new CssCommand('#page-title', array(
    'text-decoration' => 'blink',
  ));
  $command
    ->setProperty('font-size', '40px')
    ->setProperty('font-weight', 'bold');
  $expected = array(
    'command' => 'css',
    'selector' => '#page-title',
    'argument' => array(
      'text-decoration' => 'blink',
      'font-size' => '40px',
      'font-weight' => 'bold',
    ),
  );
  $this
    ->assertEqual($command
    ->render(), $expected, 'CssCommand::render() returns a proper array.');
}