public function testRemoveStyleAttribute()
{
$writer = new THtmlWriter(self::$output);
$writer->addStyleAttribute('font-size', '1em');
$writer->addStyleAttribute('background-image', 'url(image.gif)');
$writer->removeStyleAttribute('font-size');
$result = self::readAttribute($writer, '_styles');
self::assertTrue(isset($result['background-image']));
self::assertFalse(isset($result['font-size']));
}