public void testEmptyGraph() {
Graph m = new MultiUnion();
Graph g0 = graphWith( "x p y");
assertEquals( "Empty model should have size zero", 0, m.size() );
assertFalse( "Empty model should not contain another graph", m.dependsOn( g0 ) );
}
/**
A MultiUnion graph should have a MultiUnionStatisticsHandler, and that
handler should point right back to that graph.