message: test: add conflict test for OrphanPool
diff: @@ -153,13 +153,28 @@ mod tests {
  let tx4 = build_tx(vec![(tx3_hash, 0)], 1);
  + // the tx5 and its descendants(tx6) conflict with tx1
  + let tx5 = build_tx(vec![(&H256::zero(), 0)], 2);
  + let tx5_hash = tx5.hash();
  +
  + let tx6 = build_tx(vec![(tx5_hash, 0)], 1);
  +
  pool.add_tx(None, MOCK_SIZE, tx2.clone(), tx1.output_pts().into_iter());
  pool.add_tx(None, MOCK_SIZE, tx3.clone(), tx2.output_pts().into_iter());
  pool.add_tx(None, MOCK_SIZE, tx4.clone(), tx3.output_pts().into_iter());
  + pool.add_tx(
  + None,
  + MOCK_SIZE,
  + tx5.clone(),
  + tx1.inputs().to_vec().into_iter().map(|x| x.previous_output),
  + );
  + pool.add_tx(None, MOCK_SIZE, tx6.clone(), tx5.output_pts().into_iter());
  assert!(pool.contains(&tx2));
  assert!(pool.contains(&tx3));
  assert!(pool.contains(&tx4));
  + assert!(pool.contains(&tx5));
  + assert!(pool.contains(&tx6));
  let txs: Vec<_> = pool
  .remove_by_ancestor(&tx1)
  @@ -167,6 +182,9 @@ mod tests {
  .map(|e| e.transaction)
  .collect();
  + assert!(!pool.contains(&tx5));
  + assert!(!pool.contains(&tx6));
  +
  assert_eq!(txs, vec![tx2, tx3, tx4]);
  }
  @@ -197,6 +215,10 @@ mod tests {
  .collect();
  assert!(txs.is_empty());
  + assert_eq!(txs, vec![]);
  + assert!(pool.contains(&tx3));
  + assert!(pool.contains(&tx4));
  +
  let txs: Vec<_> = pool
  .remove_by_ancestor(&tx2)
  .into_iter()
  