public void TestCombine()
        {
            VertexElement[] firstElements  = VertexDeclarationHelper.BuildElementList <TestVertex>();
            VertexElement[] secondElements = VertexDeclarationHelper.BuildElementList <
                SecondStreamVertex
                >();

            VertexElement[] combinedElements =
                VertexDeclarationHelper.Combine(firstElements, secondElements);

            Assert.AreEqual(firstElements.Length + secondElements.Length, combinedElements.Length);
            CollectionAssert.IsSubsetOf(firstElements, combinedElements);
            CollectionAssert.IsSubsetOf(secondElements, combinedElements);
        }
 public void TestThrowOnCombineNull()
 {
     Assert.Throws <NullReferenceException>(
         delegate() { VertexDeclarationHelper.Combine(null, null); }
         );
 }