flushManager.buildFlushStack(graph.getHeadNode(), EventType.INSERT);
Deque<Node> fs = flushManager.getFlushStack();
Assert.assertEquals(3, fs.size());
flushManager.clearFlushStack();
flushManager = new FlushManager();
flushManager.buildFlushStack(graphb2.getHeadNode(), EventType.INSERT);
fs = flushManager.getFlushStack();
Assert.assertEquals(2, fs.size());
flushManager.clearFlushStack();
flushManager = new FlushManager();
flushManager.buildFlushStack(graphb3.getHeadNode(), EventType.INSERT);