test: add python custom persistence

Here we check that an arbitrary persister can persist and load a wallet
correctly. The test applies two unconfirmed transactions and asserts
that a first wallet that persists the changes and a second wallet that
loads from these changes will have the same values.

Author: andreasgriffin

bdk-python/tests/test_arbitrary_persistence.py

@@ -0,0 +1,80 @@
+import unittest
+from bdkpython import Descriptor, ChangeSet, Network, Persistence, Persister, Transaction, UnconfirmedTx, Wallet 
+
+initial_txs = [
+    "0200000000010101d7eb881ab8cac7d6adc6a7f9aa13e694813d95330c7299cee3623e5d14bd590000000000fdffffff02c5e6c1010000000016001407103a1cccf6a1ea654bee964a4020d20c41fb055c819725010000001600146337ec04bf42015e5d077b90cae05c06925c491a0247304402206aae2bf32da4c3b71cb95e6633c22f9f5a4a4f459975965c0c39b0ab439737b702200c4b16d2029383190965b07adeb87e6d634c68c70d2742f25e456874e8dc273a012103930326d6d72f8663340ce4341d0d3bdb1a1c0734d46e5df8a3003ab6bb50073b00000000",
+    "02000000000101b0db431cffebeeeeec19ee8a09a2ae4755722ea73232dbb99b8e754eaad6ac300100000000fdffffff024ad24201000000001600146a7b71a68b261b0b7c79e5bb00f0f3d65d5ae4a285ae542401000000160014e43ff61232ca20061ef1d241e73f322a149a23d902473044022059f4b2fa8b9da34dbb57e491f3d5b8a47a623d7e6ebc1b6adfe6d2be744c9640022073cfc8311c49a8d48d69076466d32be591d3c0092b965828cfbcaca69fd409c90121027aa62d03db46272fa31bc1a6cb095bb66bc5409dd74b25e88e3099d84a17a3e469000000",
+]
+descriptor: Descriptor = Descriptor(
+    "wpkh([44250c36/84'/1'/0']tpubDCrUjjHLB1fxk1oRveETjw62z8jsUuqx7JkBUW44VBszGmcY3Eun3apwVcE5X2bfF5MsM3uvuQDed6Do33ZN8GiWcnj2QPqVDspFT1AyZJ9/0/*)",
+    Network.REGTEST,
+)
+change_descriptor: Descriptor = Descriptor(
+    "wpkh([44250c36/84'/1'/0']tpubDCrUjjHLB1fxk1oRveETjw62z8jsUuqx7JkBUW44VBszGmcY3Eun3apwVcE5X2bfF5MsM3uvuQDed6Do33ZN8GiWcnj2QPqVDspFT1AyZJ9/1/*)",
+    Network.REGTEST,
+)
+
+
+class MyPersistence(Persistence):
+    def __init__(self):
+        self.memory = []
+
+    def merge_all(self) -> ChangeSet:
+        total_changeset = ChangeSet()
+        for changeset_dict in self.memory:
+            total_changeset = ChangeSet.from_merge(total_changeset, changeset_dict)
+        return total_changeset
+
+    def initialize(self) -> ChangeSet:
+        return self.merge_all()
+
+    def persist(self, changeset: ChangeSet):
+        self.memory.append(changeset)
+
+
+class PersistenceTest(unittest.TestCase):
+
+    def test_synced_transactions(self):
+
+        myp = MyPersistence()
+        persister = Persister.custom(myp)
+
+        wallet: Wallet = Wallet(descriptor, change_descriptor, Network.REGTEST, persister)
+
+        wallet.apply_unconfirmed_txs(
+            [UnconfirmedTx(tx=Transaction(bytes.fromhex(tx)), last_seen=0) for tx in initial_txs]
+        )
+
+        wallet.persist(persister=persister)
+
+        # initialize new wallet with memory of myp
+        myp2 = MyPersistence()
+        myp2.memory = myp.memory.copy()
+        persister2 = Persister.custom(myp2)
+
+        wallet2 = Wallet.load(
+            descriptor=descriptor,
+            change_descriptor=change_descriptor,
+            persister=persister2,
+        )
+
+        # check for equality
+        outputs = wallet.list_output()
+        outputs2 = wallet2.list_output()
+        assert len(outputs) == len(outputs2)
+        for o, o2 in zip(outputs, outputs2):
+            assert o.outpoint.txid == o2.outpoint.txid
+            assert o.outpoint.vout == o2.outpoint.vout
+
+        txs = wallet.transactions()
+        txs2 = wallet2.transactions()
+        assert txs, "Sync error"
+        assert len(txs) == len(txs2)
+        for tx, tx2 in zip(txs, txs2):
+            assert tx.transaction.compute_txid().serialize() == tx2.transaction.compute_txid().serialize()
+
+        assert wallet.balance().total.to_sat() == 50641167
+
+
+if __name__ == "__main__":
+    unittest.main()