text: #!/usr/bin/env python
  # Copyright (c) 2014 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #
  # Test spending coinbase transactions.
  # The coinbase transaction in block N can appear in block
  # N+100... so is valid in the mempool when the best block
  # height is N+99.
  # This test makes sure coinbase spends that will be mature
  # in the next block are accepted into the memory pool,
  # but less mature coinbase spends are NOT.
  #
  
  import sys; assert sys.version_info < (3,), ur"This script does not run under Python 3. Please use Python 2.7.x."
  
  from test_framework.test_framework import BitcoinTestFramework
  from test_framework.authproxy import JSONRPCException
  from test_framework.util import assert_equal, assert_greater_than, assert_raises, \
      start_node
  
  
  # Create one-input, one-output, no-fee transaction:
  class MempoolSpendCoinbaseTest(BitcoinTestFramework):
  
      def setup_network(self):
          # Just need one node for this test
          args = ["-checkmempool", "-debug=mempool"]
          self.nodes = []
          self.nodes.append(start_node(0, self.options.tmpdir, args))
          self.is_network_split = False
  
      def create_tx(self, from_txid, to_address, amount):
          inputs = [{ "txid" : from_txid, "vout" : 0}]
          outputs = { to_address : amount }
          rawtx = self.nodes[0].createrawtransaction(inputs, outputs)
          signresult = self.nodes[0].signrawtransaction(rawtx)
          assert_equal(signresult["complete"], True)
          return signresult["hex"]
  
      def run_test(self):
          chain_height = self.nodes[0].getblockcount()
          assert_equal(chain_height, 200)
          node0_address = self.nodes[0].getnewaddress()
  
          # Coinbase at height chain_height-100+1 ok in mempool, should
          # get mined. Coinbase at height chain_height-100+2 is
          # is too immature to spend.
          b = [ self.nodes[0].getblockhash(n) for n in range(101, 103) ]
          coinbase_txids = [ self.nodes[0].getblock(h)['tx'][0] for h in b ]
          spends_raw = [ self.create_tx(txid, node0_address, 10) for txid in coinbase_txids ]
  
          spend_101_id = self.nodes[0].sendrawtransaction(spends_raw[0])
  
          # coinbase at height 102 should be too immature to spend
          assert_raises(JSONRPCException, self.nodes[0].sendrawtransaction, spends_raw[1])
  
          # mempool should have just spend_101:
          mempoolinfo = self.nodes[0].getmempoolinfo()
          assert_equal(mempoolinfo['size'], 1)
          assert_equal(self.nodes[0].getrawmempool(), [ spend_101_id ])
  
          # the size of the memory pool should be greater than 1x ~100 bytes
          assert_greater_than(mempoolinfo['bytes'], 100)
          # the actual memory usage should be strictly greater than the size
          # of the memory pool
          assert_greater_than(mempoolinfo['usage'], mempoolinfo['bytes'])
  
          # mine a block, spend_101 should get confirmed
          self.nodes[0].generate(1)
          mempoolinfo = self.nodes[0].getmempoolinfo()
          assert_equal(mempoolinfo['size'], 0)
          assert_equal(mempoolinfo['bytes'], 0)
          assert_equal(mempoolinfo['usage'], 0)
          assert_equal(set(self.nodes[0].getrawmempool()), set())
  
          # ... and now height 102 can be spent:
          spend_102_id = self.nodes[0].sendrawtransaction(spends_raw[1])
          mempoolinfo = self.nodes[0].getmempoolinfo()
          assert_equal(mempoolinfo['size'], 1)
          assert_equal(self.nodes[0].getrawmempool(), [ spend_102_id ])
          assert_greater_than(mempoolinfo['bytes'], 100)
          assert_greater_than(mempoolinfo['usage'], mempoolinfo['bytes'])
  
  if __name__ == '__main__':
      MempoolSpendCoinbaseTest().main()
  