From ed7d2246661ec1789b7db0f21668270f0681ea4a Mon Sep 17 00:00:00 2001
From: Sebastian Falbesoner <sebastian.falbesoner@gmail.com>
Date: Tue, 3 Sep 2024 21:55:02 +0200
Subject: [PATCH 1/2] test: add `BulkTransaction` helper to unit test
 transaction utils

The padding method used matches the one used in MiniWallet,
`MiniWallet._bulk_tx`.
---
 src/test/util/transaction_utils.cpp | 21 +++++++++++++++++++++
 src/test/util/transaction_utils.h   |  4 ++++
 2 files changed, 25 insertions(+)

diff --git a/src/test/util/transaction_utils.cpp b/src/test/util/transaction_utils.cpp
index 300caa577ca10..5727da4444081 100644
--- a/src/test/util/transaction_utils.cpp
+++ b/src/test/util/transaction_utils.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <coins.h>
+#include <consensus/validation.h>
 #include <script/signingprovider.h>
 #include <test/util/transaction_utils.h>
 
@@ -69,3 +70,23 @@ std::vector<CMutableTransaction> SetupDummyInputs(FillableSigningProvider& keyst
 
     return dummyTransactions;
 }
+
+void BulkTransaction(CMutableTransaction& tx, int32_t target_weight)
+{
+    tx.vout.emplace_back(0, CScript() << OP_RETURN);
+    auto unpadded_weight{GetTransactionWeight(CTransaction(tx))};
+    assert(target_weight >= unpadded_weight);
+
+    // determine number of needed padding bytes by converting weight difference to vbytes
+    auto dummy_vbytes = (target_weight - unpadded_weight + (WITNESS_SCALE_FACTOR - 1)) / WITNESS_SCALE_FACTOR;
+    // compensate for the increase of the compact-size encoded script length
+    // (note that the length encoding of the unpadded output script needs one byte)
+    dummy_vbytes -= GetSizeOfCompactSize(dummy_vbytes) - 1;
+
+    // pad transaction by repeatedly appending a dummy opcode to the output script
+    tx.vout[0].scriptPubKey.insert(tx.vout[0].scriptPubKey.end(), dummy_vbytes, OP_1);
+
+    // actual weight should be at most 3 higher than target weight
+    assert(GetTransactionWeight(CTransaction(tx)) >= target_weight);
+    assert(GetTransactionWeight(CTransaction(tx)) <= target_weight + 3);
+}
diff --git a/src/test/util/transaction_utils.h b/src/test/util/transaction_utils.h
index 6f2faeec6c250..80f2d1acbf704 100644
--- a/src/test/util/transaction_utils.h
+++ b/src/test/util/transaction_utils.h
@@ -26,4 +26,8 @@ CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CSc
 // the second nValues[2] and nValues[3] outputs paid to a TxoutType::PUBKEYHASH.
 std::vector<CMutableTransaction> SetupDummyInputs(FillableSigningProvider& keystoreRet, CCoinsViewCache& coinsRet, const std::array<CAmount,4>& nValues);
 
+// bulk transaction to reach a certain target weight,
+// by appending a single output with padded output script
+void BulkTransaction(CMutableTransaction& tx, int32_t target_weight);
+
 #endif // BITCOIN_TEST_UTIL_TRANSACTION_UTILS_H

From 66d13c870284327abc89d36c0b5cc5f58e96f570 Mon Sep 17 00:00:00 2001
From: Sebastian Falbesoner <sebastian.falbesoner@gmail.com>
Date: Tue, 3 Sep 2024 21:59:12 +0200
Subject: [PATCH 2/2] test: add check that large txs aren't put into orphanage

---
 src/test/orphanage_tests.cpp | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/test/orphanage_tests.cpp b/src/test/orphanage_tests.cpp
index d4c52d7fe1038..799f2c0fec489 100644
--- a/src/test/orphanage_tests.cpp
+++ b/src/test/orphanage_tests.cpp
@@ -3,12 +3,15 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <arith_uint256.h>
+#include <consensus/validation.h>
+#include <policy/policy.h>
 #include <primitives/transaction.h>
 #include <pubkey.h>
 #include <script/sign.h>
 #include <script/signingprovider.h>
 #include <test/util/random.h>
 #include <test/util/setup_common.h>
+#include <test/util/transaction_utils.h>
 #include <txorphanage.h>
 
 #include <array>
@@ -370,4 +373,21 @@ BOOST_AUTO_TEST_CASE(get_children)
     }
 }
 
+BOOST_AUTO_TEST_CASE(too_large_orphan_tx)
+{
+    TxOrphanage orphanage;
+    CMutableTransaction tx;
+    tx.vin.resize(1);
+
+    // check that txs larger than MAX_STANDARD_TX_WEIGHT are not added to the orphanage
+    BulkTransaction(tx, MAX_STANDARD_TX_WEIGHT + 4);
+    BOOST_CHECK_EQUAL(GetTransactionWeight(CTransaction(tx)), MAX_STANDARD_TX_WEIGHT + 4);
+    BOOST_CHECK(!orphanage.AddTx(MakeTransactionRef(tx), 0));
+
+    tx.vout.clear();
+    BulkTransaction(tx, MAX_STANDARD_TX_WEIGHT);
+    BOOST_CHECK_EQUAL(GetTransactionWeight(CTransaction(tx)), MAX_STANDARD_TX_WEIGHT);
+    BOOST_CHECK(orphanage.AddTx(MakeTransactionRef(tx), 0));
+}
+
 BOOST_AUTO_TEST_SUITE_END()