public void ProcessedWithSingleQuotes_KeepQuotes() {
var reader = GetReader("body { background: url('a/url.png'); }");
var asset = new CssAsset(_context, _settings) { Path = "", Reader = reader };
var processer = new CssRelativePathProcessor(_urlManager.Object);
processer.Process(new[] { asset });
_urlManager.Verify(manager => manager.GetAbsoluteUrl(It.IsAny<string>(), It.IsAny<string>()), Times.Once());
Assert.That(asset.Reader.Content, Contains.Substring("url('"));
Assert.That(asset.Reader.Content, Contains.Substring("')"));
}