public void CheckIfContainsPersonWithSuchName()
{
DatabaseExtended db = new DatabaseExtended();
db.Add(new Person(12, "Todor"));
Assert.Throws <InvalidOperationException>(() => db.FindByUsername(null), "The name should not be null!");
}
public void CheckIfContainsPersonWithSuchName(string name)
{
DatabaseExtended db = new DatabaseExtended();
db.Add(new Person(12, "Todor"));
Assert.Throws <InvalidOperationException>(() => db.FindByUsername(name), "There is not such name");
}