Add opreturn example

lib/contracts/using_opreturn.rb

@@ -0,0 +1,68 @@
+# 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
+
+@alice = key wif: 'L4bEFrQrfXH9mZBbq2SoTEx8FkyrG4aP2TZerN8DwSTaGoUcohJd'
+@bob = key wif: 'KyWBUpCZF5n9WifoBcDDtCGYmX13SkubfQp3zCiDA4r2vozL5jE8'
+
+# Seed alice with some coins
+extend_chain to: @alice
+
+# Seed bob with some coins and make coinbase spendable
+extend_chain num_blocks: 101, to: @alice
+
+@alice_coinbase = spendable_coinbase_for @alice
+
+@data = 'ABCD'
+
+@opcodes_tx = transaction inputs: [
+                            { tx: @alice_coinbase, vout: 0, script_sig: 'sig:@alice @alice' }
+                          ],
+                          outputs: [
+                            {
+                              script: 'OP_DUP OP_HASH160 hash160(@bob) OP_EQUALVERIFY OP_CHECKSIG',
+                              amount: 49.999.sats
+                            },
+                            {
+                              script: 'OP_RETURN "ABCD"',
+                              amount: 0
+                            }
+                          ]
+
+verify_signature for_transaction: @opcodes_tx,
+                 at_index: 0,
+                 with_prevout: [@alice_coinbase, 0]
+
+broadcast @opcodes_tx
+
+confirm transaction: @opcodes_tx, to: @alice
+
+log 'Opcodes transaction confirmed'
+
+@spend_opcodes_tx = transaction inputs: [
+                                  { tx: @opcodes_tx, vout: 0, script_sig: 'sig:wpkh(@bob)' }
+                                ],
+                                outputs: [
+                                  { descriptor: 'wpkh(@bob)', amount: 49.998.sats }
+                                ]
+
+broadcast @spend_opcodes_tx

spec/runner_spec.rb

@@ -30,6 +30,7 @@
 RSpec.describe Runner.instance do
   describe 'Running DSL scripts' do
     it_behaves_like 'script evaluation', './lib/contracts/using_bitcoin_script.rb'
+    it_behaves_like 'script evaluation', './lib/contracts/using_opreturn.rb'
 
     it_behaves_like 'script evaluation', './lib/contracts/anchor_transactions.rb'
     it_behaves_like 'script evaluation', './lib/contracts/fold_transactions.rb'