public void TestUpdatedContent_WithValidUrl()
{
Catalog catalog = new Catalog();
Content firstItem = new Content(ContentType.Book, new string[] { "Intro C#", "S.Nakov", "12763892", "http://www.introprogramming.info" });
Content secondItem = new Content(ContentType.Book, new string[] { "Intro C#", "S.Nakov", "12763892", "http://www.introprogramming.info" });
Content thirdItem = new Content(ContentType.Song, new string[] { "Master of puppets", "Metallica", "2342332", "http://www.metallica.info" });
catalog.AddContent(firstItem);
catalog.AddContent(secondItem);
catalog.AddContent(thirdItem);
var result = catalog.UpdatedContent("http://www.introprogramming.info", "http://www.introprogramming.se");
Assert.AreEqual(2, result);
}