text: #!/usr/bin/env python3
  # Copyright (c) 2014-2016 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.
  #
  
  from test_framework.test_framework import BsmCoinTestFramework
  from test_framework.util import *
  
  # Create one-input, one-output, no-fee transaction:
  class MempoolSpendCoinbaseTest(BsmCoinTestFramework):
  
      def __init__(self):
          super().__init__()
          self.num_nodes = 1
          self.setup_clean_chain = True
  
      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 run_test(self):
          slow_gen(self.nodes[0], 10)
          chain_height = self.nodes[0].getblockcount()
          assert_equal(chain_height, 10)
          node0_address = self.nodes[0].getnewaddress()
  
          # Coinbase at height chain_height-5+1 ok in mempool, should
          # get mined. Coinbase at height chain_height-5+2 is
          # is too immature to spend.
          b = [ self.nodes[0].getblockhash(n) for n in range(6, 8) ]
          coinbase_txids = [ self.nodes[0].getblock(h)['tx'][0] for h in b ]
          spends_raw = [ create_tx(self.nodes[0], txid, node0_address, 49.99) for txid in coinbase_txids ]
  
          spend_6_id = self.nodes[0].sendrawtransaction(spends_raw[0])
  
          # coinbase at height 7 should be too immature to spend
          assert_raises(JSONRPCException, self.nodes[0].sendrawtransaction, spends_raw[1])
  
          # mempool should have just spend_6:
          assert_equal(self.nodes[0].getrawmempool(), [ spend_6_id ])
  
          # mine a block, spend_151 should get confirmed
          slow_gen(self.nodes[0], 1)
          assert_equal(set(self.nodes[0].getrawmempool()), set())
  
          # ... and now height 7 can be spent:
          spend_7_id = self.nodes[0].sendrawtransaction(spends_raw[1])
          assert_equal(self.nodes[0].getrawmempool(), [ spend_7_id ])
  
  if __name__ == '__main__':
      MempoolSpendCoinbaseTest().main()
  