Add spending multiple inputs example

lib/contracts/multiple_inputs.rb

@@ -0,0 +1,55 @@
+# Copyright 2024 Kulpreet Singh
+#
+# This file is part of Bitcoin-DSL
+#
+# Bitcoin-DSL is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bitcoin-DSL is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bitcoin-DSL. If not, see <https://www.gnu.org/licenses/>.
+
+# frozen_string_literal: false
+
+# Generate new keys
+@alice = key :new
+@bob = key :new
+@carol = key :new
+
+# Seed alice with some coins
+extend_chain to: @alice
+
+# Seed bob with some coins and make coinbase spendable
+extend_chain num_blocks: 1, to: @alice
+extend_chain num_blocks: 101, to: @bob
+
+@alice_coinbase = spendable_coinbase_for @alice
+@bob_coinbase = spendable_coinbase_for @bob
+
+@multiple_inputs_tx = transaction inputs: [
+                                   { tx: @alice_coinbase, vout: 0, script_sig: 'sig:wpkh(@alice)' },
+                                   { tx: @bob_coinbase, vout: 0, script_sig: 'sig:wpkh(@bob)' }
+                                 ],
+                                 outputs: [
+                                   {
+                                     descriptor: 'wpkh(@carol)',
+                                     amount: 99.999.sats
+                                   }
+                                 ]
+
+# verify_signature for_transaction: @multiple_inputs_tx,
+#                  at_index: 0,
+#                  with_prevout: [@alice_coinbase, 0]
+
+assert_mempool_accept @multiple_inputs_tx
+broadcast @multiple_inputs_tx
+confirm transaction: @multiple_inputs_tx, to: @carol
+
+assert_output_is_spent transaction: @alice_coinbase, vout: 0
+assert_output_is_spent transaction: @bob_coinbase, vout: 0

spec/runner_spec.rb

@@ -35,6 +35,7 @@
     it_behaves_like 'script evaluation', './lib/contracts/anchor_transactions.rb'
     it_behaves_like 'script evaluation', './lib/contracts/fold_transactions.rb'
     it_behaves_like 'script evaluation', './lib/contracts/multisig.rb'
+    it_behaves_like 'script evaluation', './lib/contracts/multiple_inputs.rb'
     it_behaves_like 'script evaluation', './lib/contracts/simple.rb'
   end