public void TestVertexCountAndTrim()
{
var graph = new DirectedMetaGraph(1, 1, 10);
// add edge.
graph.AddEdge(0, 1, 1, 100);
// trim.
graph.Trim();
Assert.AreEqual(2, graph.VertexCount);
graph = new DirectedMetaGraph(1, 1, 10);
// add edge.
graph.AddEdge(0, 1, 1, 100);
graph.AddEdge(0, 11001, 1, 100);
// trim.
graph.Trim();
Assert.AreEqual(11002, graph.VertexCount);
graph = new DirectedMetaGraph(1, 1, 10);
// trim.
graph.Trim(); // keep minimum one vertex.
Assert.AreEqual(1, graph.VertexCount);
}