public void TestMatch()
{
var gr1 = new Graph();
var gr2 = new Graph();
var vfs = new VfState(gr1, gr2);
var match = vfs.Match();
Assert.IsNotNull(match); // Two empty graphs match
gr2.InsertVertex();
vfs = new VfState(gr1, gr2);
match = vfs.Match();
Assert.IsNull(match); // Graph with no vertices will not match one with a single isolated vertex
gr1.InsertVertex();
vfs = new VfState(gr1, gr2);
match = vfs.Match();
Assert.IsNotNull(match); // Two graphs with single isolated vertices match
gr1.InsertVertex();
vfs = new VfState(gr1, gr2);
match = vfs.Match();
Assert.IsNotNull(match); // Two isolated vertices match with one under default subgraph isomorphism
gr1.AddEdge(0, 1);
vfs = new VfState(gr1, gr2);
match = vfs.Match();
Assert.IsNotNull(match); // Connect the two and a subgraph isomorphism still works
}