Merge #13669: Tests: Cleanup create_transaction implementations

44bbceeef1 [Tests] Cleanup feature_block.py, remove unnecessary PreviousSpendableOutput object (Conor Scott)
736f941424 [Tests] Cleanup extra instances of create_transaction (Conor Scott)
157651855f [Tests] Rename create_tx and move to blocktools.py (Conor Scott)

Pull request description:

  There currently exist seven ([1](https://github.com/bitcoin/bitcoin/blob/master/test/functional/feature_cltv.py#L52-L60), [2](https://github.com/bitcoin/bitcoin/blob/master/test/functional/feature_csv_activation.py#L88-L95) [3](https://github.com/bitcoin/bitcoin/blob/master/test/functional/feature_dersig.py#L40-L48), [4](https://github.com/bitcoin/bitcoin/blob/master/test/functional/feature_nulldummy.py#L100-L108), [5](https://github.com/bitcoin/bitcoin/blob/master/test/functional/test_framework/util.py#L529-L535), [6](https://github.com/bitcoin/bitcoin/blob/master/test/functional/test_framework/blocktools.py#L120-L129), [7](https://github.com/bitcoin/bitcoin/blob/master/test/functional/feature_block.py#L1218-L1220)) implementations of a function called something similar to `create_transaction` in the functional tests, some of which are exact copies of each other.

  This PR aims to clean this up into [three different cases implemented in blocktools.py](https://github.com/conscott/bitcoin/blob/create_tx_cleanup/test/functional/test_framework/blocktools.py#L121-L149)
  1. `create_tx_with_script`: Return transaction object spending generic tx output optionally specifying scriptSig and scriptPubKey
  2. `create_transaction`: Return transaction object spending coinbase tx
  2. `create_raw_transaction`: Return raw transaction (hex string) spending coinbase tx

  I am not committed to any of these function names, so I'll gladly take suggestions on there.

  Additionally there are some related cleanups to feature_block.py tests, specifically removing the [PreviousSpendableOutput](https://github.com/conscott/bitcoin/blob/master/test/functional/feature_block.py#L51-L54) object, which seems like an unnecessary layer given that every instance spends the 0 output.

Tree-SHA512: 63c6233b6f0942c81ba1ca67ea6770809b8c9409314c6d4cf8e5a3991cb9ee92b22bebe88c0dde45cd71e754eb351230c4c404b70ff118f5f43c034452ada65c

test/functional/test_framework/blocktools.py

@@ -39,6 +39,7 @@ from .script import (
     hash160,
 )
 from .util import assert_equal
+from io import BytesIO
 
 # From BIP141
 WITNESS_COMMITMENT_HEADER = b"\xaa\x21\xa9\xed"
@@ -117,17 +118,43 @@ def create_coinbase(height, pubkey=None):
     coinbase.calc_sha256()
     return coinbase
 
-def create_transaction(prevtx, n, sig, value, script_pub_key=CScript()):
-    """Create a transaction.
+def create_tx_with_script(prevtx, n, script_sig=b"", amount=1, script_pub_key=CScript()):
+    """Return one-input, one-output transaction object
+       spending the prevtx's n-th output with the given amount.
 
-    If the script_pub_key is not specified, make it anyone-can-spend."""
+       Can optionally pass scriptPubKey and scriptSig, default is anyone-can-spend ouput.
+    """
     tx = CTransaction()
     assert(n < len(prevtx.vout))
-    tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), sig, 0xffffffff))
-    tx.vout.append(CTxOut(value, script_pub_key))
+    tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), script_sig, 0xffffffff))
+    tx.vout.append(CTxOut(amount, script_pub_key))
     tx.calc_sha256()
     return tx
 
+def create_transaction(node, txid, to_address, amount):
+    """ Return signed transaction spending the first output of the
+        input txid. Note that the node must be able to sign for the
+        output that is being spent, and the node must not be running
+        multiple wallets.
+    """
+    raw_tx = create_raw_transaction(node, txid, to_address, amount)
+    tx = CTransaction()
+    tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx)))
+    return tx
+
+def create_raw_transaction(node, txid, to_address, amount):
+    """ Return raw signed transaction spending the first output of the
+        input txid. Note that the node must be able to sign for the
+        output that is being spent, and the node must not be running
+        multiple wallets.
+    """
+    inputs = [{"txid": txid, "vout": 0}]
+    outputs = {to_address: amount}
+    rawtx = node.createrawtransaction(inputs, outputs)
+    signresult = node.signrawtransactionwithwallet(rawtx)
+    assert_equal(signresult["complete"], True)
+    return signresult['hex']
+
 def get_legacy_sigopcount_block(block, accurate=True):
     count = 0
     for tx in block.vtx:

test/functional/test_framework/util.py

@@ -526,14 +526,6 @@ def gen_return_txouts():
         txouts = txouts + script_pubkey
     return txouts
 
-def create_tx(node, coinbase, to_address, amount):
-    inputs = [{"txid": coinbase, "vout": 0}]
-    outputs = {to_address: amount}
-    rawtx = node.createrawtransaction(inputs, outputs)
-    signresult = node.signrawtransactionwithwallet(rawtx)
-    assert_equal(signresult["complete"], True)
-    return signresult["hex"]
-
 # Create a spend of each passed-in utxo, splicing in "txouts" to each raw
 # transaction to make it large.  See gen_return_txouts() above.
 def create_lots_of_big_transactions(node, txouts, utxos, num, fee):