test: refactor: support sending funds with outpoint result

This commit introduces a helper `create_outpoints` to execute the
`send` RPC and immediately return the target address outpoints as UTXO
dictionary in the common format, making the tests more readable and
avoiding unnecessary duplication.

test/functional/test_framework/test_framework.py

@@ -30,6 +30,7 @@ from .util import (
     PortSeed,
     assert_equal,
     check_json_precision,
+    find_vout_for_address,
     get_datadir_path,
     initialize_datadir,
     p2p_port,
@@ -697,6 +698,22 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
         sync_fun() if sync_fun else self.sync_all()
         return blocks
 
+    def create_outpoints(self, node, *, outputs):
+        """Send funds to a given list of `{address: amount}` targets using the bitcoind
+        wallet and return the corresponding outpoints as a list of dictionaries
+        `[{"txid": txid, "vout": vout1}, {"txid": txid, "vout": vout2}, ...]`.
+        The result can be used to specify inputs for RPCs like `createrawtransaction`,
+        `createpsbt`, `lockunspent` etc."""
+        assert all(len(output.keys()) == 1 for output in outputs)
+        send_res = node.send(outputs)
+        assert send_res["complete"]
+        utxos = []
+        for output in outputs:
+            address = list(output.keys())[0]
+            vout = find_vout_for_address(node, send_res["txid"], address)
+            utxos.append({"txid": send_res["txid"], "vout": vout})
+        return utxos
+
     def sync_blocks(self, nodes=None, wait=1, timeout=60):
         """
         Wait until everybody has the same tip.