vertices[i] = new DesignerVertex(catalog_tbl);
dgraph.addVertex(vertices[i]);
if (i > 0) {
for (int j = 0; j < num_edges; j++) {
dgraph.addEdge(new DesignerEdge(dgraph), vertices[i-1], vertices[i]);
} // FOR
Collection<DesignerEdge> edges = dgraph.findEdgeSet(vertices[i-1], vertices[i]);
assertNotNull(edges);
assertEquals(num_edges, edges.size());
}