public void TestHasPackage()
        {
            repositoryOne.AddPackage(Helper.MockPackage("foo", "1.0"));
            repositoryTwo.AddPackage(Helper.MockPackage("bar", "1.0"));

            Assert.IsTrue(repositoryComposite.HasPackage(Helper.MockPackage("foo", "1.0")));
            Assert.IsTrue(repositoryComposite.HasPackage(Helper.MockPackage("bar", "1.0")));

            Assert.IsFalse(repositoryComposite.HasPackage(Helper.MockPackage("foo", "2.0")));
            Assert.IsFalse(repositoryComposite.HasPackage(Helper.MockPackage("bar", "2.0")));
        }