tests: toyserver: add faucet

diff --git a/tests/test_interface.py b/tests/test_interface.py
index 9012afe..b730bf7 100644
--- a/tests/test_interface.py
+++ b/tests/test_interface.py
@@ -11,6 +11,7 @@ from electrum.util import OldTaskGroup, bfh
 from electrum.simple_config import SimpleConfig
 from electrum.transaction import Transaction, TxOutput
 from electrum.wallet import Abstract_Wallet
+from electrum.address_synchronizer import TX_HEIGHT_UNCONFIRMED
 from electrum.blockchain import Blockchain
 
 from . import ElectrumTestCase
@@ -115,7 +116,7 @@ class TestInterface(ElectrumTestCase):
         self.network = MockNetwork(config=self.config)
         for _ in range(10):  # mine some blocks
             await self._toyserver.mine_block()
-
+        await self._toyserver.set_up_faucet(config=self.config)
 
     async def asyncTearDown(self):
         if self.network.interface:
@@ -179,17 +180,18 @@ class TestInterface(ElectrumTestCase):
         await w1.up_to_date_changed_event.wait()
         self.assertEqual(self._get_server_session()._method_counts["blockchain.scripthash.get_history"], 0)
         # fund w1 (in mempool)
-        funding_tx = Transaction("01000000000101e855888b77b1688d08985b863bfe85b354049b4eba923db9b5cf37089975d5d10000000000fdffffff0280969800000000001600140297bde2689a3c79ffe050583b62f86f2d9dae5460abe9000000000016001472df47551b6e7e0c8428814d2e572bc5ac773dda024730440220383efa2f0f5b87f8ce5d6b6eaf48cba03bf522b23fbb23b2ac54ff9d9a8f6a8802206f67d1f909f3c7a22ac0308ac4c19853ffca3a9317e1d7e0c88cc3a86853aaac0121035061949222555a0df490978fe6e7ebbaa96332ecb5c266918fd800c0eef736e7358d1400")
-        funding_txid = await self._toyserver.mempool_add_tx(funding_tx)
+        w1_addr = w1.get_receiving_address()
+        funding_tx = await self._toyserver.ask_faucet([TxOutput.from_address_and_value(w1_addr, 1 * COIN)])
+        funding_txid = funding_tx.txid()
         await w1.up_to_date_changed_event.wait()
         while not w1.is_up_to_date():
             await w1.up_to_date_changed_event.wait()
         self.assertEqual(self._get_server_session()._method_counts["blockchain.scripthash.get_history"], 1)
         self.assertEqual(
-            w1.adb.get_address_history("bcrt1qq2tmmcngng78nllq2pvrkchcdukemtj5jnxz44"),
+            w1.adb.get_address_history(w1_addr),
             {funding_txid: 0})
         # mine funding tx
-        await self._toyserver.mine_block(txs=[Transaction(funding_tx)])
+        await self._toyserver.mine_block(txs=[funding_tx])
         server_blockheight += 1
         await w1.up_to_date_changed_event.wait()
         while not w1.is_up_to_date():
@@ -197,6 +199,6 @@ class TestInterface(ElectrumTestCase):
         # see if we managed to guess new history, and hence did not need to call get_history RPC
         self.assertEqual(self._get_server_session()._method_counts["blockchain.scripthash.get_history"], 1)
         self.assertEqual(
-            w1.adb.get_address_history("bcrt1qq2tmmcngng78nllq2pvrkchcdukemtj5jnxz44"),
+            w1.adb.get_address_history(w1_addr),
             {funding_txid: server_blockheight})
 
diff --git a/tests/toyserver.py b/tests/toyserver.py
index 7ed07a3..c8073a3 100644
--- a/tests/toyserver.py
+++ b/tests/toyserver.py
@@ -14,10 +14,16 @@ from aiorpcx import RPCError
 from electrum import blockchain
 from electrum.util import bfh
 from electrum.logging import Logger
-from electrum.transaction import Transaction, TxOutput, TxInput, TxOutpoint
+from electrum.transaction import Transaction, TxOutput, TxInput, TxOutpoint, PartialTxOutput
 from electrum import constants
-from electrum.bitcoin import script_to_scripthash
+from electrum.bitcoin import script_to_scripthash, COIN, COINBASE_MATURITY
+from electrum.simple_config import SimpleConfig
 from electrum.synchronizer import history_status
+from electrum.wallet import Abstract_Wallet
+from electrum.address_synchronizer import TX_HEIGHT_UNCONFIRMED
+from electrum.fee_policy import FixedFeePolicy
+
+from . import restore_wallet_from_text__for_unittest
 
 
 DAEMON_ERROR = 2
@@ -48,6 +54,8 @@ class ToyServer:
         self._cache_blockheight_from_txid = {}  # type: dict[str, int]
         self.txo_to_spender_txid = {}  # type: dict[TxOutpoint, str | None]  # also contains UTXOs
 
+        self._faucet_w = None  # type: Optional[Abstract_Wallet]
+
     async def start(self):
         session_factory = partial(ToyServerSession, toyserver=self)
         self.asyncio_server = await aiorpcx.serve_rs(session_factory, "127.0.0.1")
@@ -191,6 +199,29 @@ class ToyServer:
             await session.server_send_notifications(touched_sh=touched_sh, height_changed=True)
         return new_block, coinbase_tx
 
+    async def set_up_faucet(self, *, config: SimpleConfig):
+        assert self._faucet_w is None
+        self._faucet_w = restore_wallet_from_text__for_unittest(
+            "9dk", passphrase="faucet", path=None, config=config)['wallet']  # type: Abstract_Wallet
+        self._faucet_w.adb.get_local_height = lambda *args: self.cur_height
+        faucet_cb_txo = TxOutput.from_address_and_value(self._faucet_w.get_receiving_address(), 50 * COIN)
+        block, cb_tx = await self.mine_block(coinbase_outputs=[faucet_cb_txo])
+        faucet_tx_height = self.cur_height
+        for _ in range(COINBASE_MATURITY):  # need to mine some blocks for maturity
+            await self.mine_block()
+        self._faucet_w.adb.receive_tx_callback(cb_tx, tx_height=faucet_tx_height)
+        # note: balance is unverified due to lack of SPV, gets treated as "unconfirmed":
+        assert self._faucet_w.get_balance() == (0, 50 * COIN, 0), self._faucet_w.get_balance()
+
+    async def ask_faucet(self, outputs: Sequence[TxOutput]) -> Transaction:
+        assert self._faucet_w, "faucet must be set up first using set_up_faucet()"
+        outputs = [PartialTxOutput.from_txout(txout) for txout in outputs]
+        tx = self._faucet_w.make_unsigned_transaction(outputs=outputs, fee_policy=FixedFeePolicy(0))
+        self._faucet_w.sign_transaction(tx, password=None)
+        self._faucet_w.adb.receive_tx_callback(tx, tx_height=TX_HEIGHT_UNCONFIRMED)
+        await self.mempool_add_tx(tx)
+        return tx
+
 
 class ToyServerSession(aiorpcx.RPCSession, Logger):
     """Server-side representation of a single electrum-protocol session."""