public void TestBackground()
{
// should support background
Transformation transformation = new Transformation().Background("red");
String result = m_api.UrlImgUp.Transform(transformation).BuildUrl("test");
Assert.AreEqual(m_defaultImgUpPath + "b_red/test", result);
transformation = new Transformation().Background("#112233");
result = m_api.UrlImgUp.Transform(transformation).BuildUrl("test");
Assert.AreEqual(m_defaultImgUpPath + "b_rgb:112233/test", result);
}