Merge #20039: test: Convert amounts from float to decimal

5aadd4b Convert amounts from float to decimal (Prayank)

Pull request description:

  > decimal is preferred in accounting applications

  https://docs.python.org/3.8/library/decimal.html

  Decimal type saves an exact value so better than using float.

  ~~3 variables declared with type as 'Decimal' in [test/functional/mempool_accept.py](https://github.com/bitcoin/bitcoin/blob/master/test/functional/mempool_accept.py): fee, fee_expected, output_amount~~

  ~~Not required to convert to string anymore for using the above variables as decimal~~

  + fee, fee_expected, output_amount
  ~~+ 8 decimal places~~
  + Using value of coin['amount'] as decimal and removed 'int'
  + Removed unnecessary parentheses
  + Remove str() and use quotes

  Fixes bitcoin/bitcoin#20011

ACKs for top commit:
  guggero:
    ACK 5aadd4b

Tree-SHA512: 5877cf3837e5b65bec0fc8909de141a720bfa02a747513e21d20f3c41ec0cfecc524d2c347a96596b0a1a97900da2acf08b799f26b11d537e4dcddc6ce45f38e

Author: MarcoFalke

test/functional/mempool_accept.py

@@ -83,31 +83,31 @@ def run_test(self):
         )
 
         self.log.info('A transaction not in the mempool')
-        fee = 0.00000700
+        fee = Decimal('0.000007')
         raw_tx_0 = node.signrawtransactionwithwallet(node.createrawtransaction(
             inputs=[{"txid": txid_in_block, "vout": 0, "sequence": BIP125_SEQUENCE_NUMBER}],  # RBF is used later
-            outputs=[{node.getnewaddress(): 0.3 - fee}],
+            outputs=[{node.getnewaddress(): Decimal('0.3') - fee}],
         ))['hex']
         tx = CTransaction()
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_0)))
         txid_0 = tx.rehash()
         self.check_mempool_result(
-            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': Decimal(str(fee))}}],
+            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': fee}}],
             rawtxs=[raw_tx_0],
         )
 
         self.log.info('A final transaction not in the mempool')
         coin = coins.pop()  # Pick a random coin(base) to spend
-        output_amount = 0.025
+        output_amount = Decimal('0.025')
         raw_tx_final = node.signrawtransactionwithwallet(node.createrawtransaction(
             inputs=[{'txid': coin['txid'], 'vout': coin['vout'], "sequence": 0xffffffff}],  # SEQUENCE_FINAL
             outputs=[{node.getnewaddress(): output_amount}],
             locktime=node.getblockcount() + 2000,  # Can be anything
         ))['hex']
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_final)))
-        fee_expected = int(coin['amount']) - output_amount
+        fee_expected = coin['amount'] - output_amount
         self.check_mempool_result(
-            result_expected=[{'txid': tx.rehash(), 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': Decimal(str(fee_expected))}}],
+            result_expected=[{'txid': tx.rehash(), 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': fee_expected}}],
             rawtxs=[tx.serialize().hex()],
             maxfeerate=0,
         )
@@ -130,7 +130,7 @@ def run_test(self):
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_0)))
         txid_0 = tx.rehash()
         self.check_mempool_result(
-            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': Decimal(str(2 * fee))}}],
+            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': (2 * fee)}}],
             rawtxs=[raw_tx_0],
         )
 
@@ -190,7 +190,7 @@ def run_test(self):
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         # Reference tx should be valid on itself
         self.check_mempool_result(
-            result_expected=[{'txid': tx.rehash(), 'allowed': True, 'vsize': tx.get_vsize(), 'fees': { 'base': Decimal(str(0.1 - 0.05))}}],
+            result_expected=[{'txid': tx.rehash(), 'allowed': True, 'vsize': tx.get_vsize(), 'fees': { 'base': Decimal('0.1') - Decimal('0.05')}}],
             rawtxs=[tx.serialize().hex()],
             maxfeerate=0,
         )