test: add unit test for non-standard txs with too large scriptSig

The function IsStandardTx() returns rejection reason "scriptsig-size" if any
one the inputs' scriptSig is larger than 1650 bytes.

Author: theStack

src/test/transaction_tests.cpp

@@ -784,6 +784,19 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     reason.clear();
     BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
     BOOST_CHECK_EQUAL(reason, "multi-op-return");
+
+    // Check large scriptSig (non-standard if size is >1650 bytes)
+    t.vout.resize(1);
+    t.vout[0].nValue = MAX_MONEY;
+    t.vout[0].scriptPubKey = GetScriptForDestination(PKHash(key.GetPubKey()));
+    // OP_PUSHDATA2 with len (3 bytes) + data (1647 bytes) = 1650 bytes
+    t.vin[0].scriptSig = CScript() << std::vector<unsigned char>(1647, 0); // 1650
+    BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
+
+    t.vin[0].scriptSig = CScript() << std::vector<unsigned char>(1648, 0); // 1651
+    reason.clear();
+    BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
+    BOOST_CHECK_EQUAL(reason, "scriptsig-size");
 }
 
 BOOST_AUTO_TEST_SUITE_END()