public void TestRemoveBySubjectRemovesAllMatches()
{
var c = new TripleCollection();
c.AddRange(new [] { T1, T2, T3, T4 });
Assert.AreEqual(4, c.Count());
c.RemoveBySubject("http://example.org/s");
Assert.AreEqual(1, c.Count());
Assert.IsTrue(c.Items.Any(x => x.Equals(T4)));
}