diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index 11d5a8ae55..34176626f0 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -72,17 +72,16 @@ static std::map<std::string, unsigned int> mapFlagNames = {
 
 unsigned int ParseScriptFlags(std::string strFlags)
 {
-    if (strFlags.empty() || strFlags == "NONE") return 0;
-    unsigned int flags = 0;
-    std::vector<std::string> words = SplitString(strFlags, ',');
+    unsigned int flags = SCRIPT_VERIFY_NONE;
+    if (strFlags.empty() || strFlags == "NONE") return flags;
 
+    std::vector<std::string> words = SplitString(strFlags, ',');
     for (const std::string& word : words)
     {
         if (!mapFlagNames.count(word))
             BOOST_ERROR("Bad test: unknown verification flag '" << word << "'");
         flags |= mapFlagNames[word];
     }
-
     return flags;
 }
 
@@ -98,7 +97,7 @@ bool CheckMapFlagNames()
 
 std::string FormatScriptFlags(unsigned int flags)
 {
-    if (flags == 0) {
+    if (flags == SCRIPT_VERIFY_NONE) {
         return "";
     }
     std::string ret;
@@ -370,6 +369,41 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
     }
 }
 
+BOOST_AUTO_TEST_CASE(tx_no_inputs)
+{
+    CMutableTransaction empty;
+
+    TxValidationState state;
+    BOOST_CHECK_MESSAGE(!CheckTransaction(CTransaction(empty), state), "Transaction with no inputs should be invalid.");
+    BOOST_CHECK(state.GetRejectReason() == "bad-txns-vin-empty");
+}
+
+BOOST_AUTO_TEST_CASE(tx_oversized)
+{
+    auto createTransaction =[](size_t payloadSize) {
+        CMutableTransaction tx;
+        tx.vin.resize(1);
+        tx.vout.emplace_back(1, CScript() << OP_RETURN << std::vector<unsigned char>(payloadSize));
+        return CTransaction(tx);
+    };
+    const auto maxTransactionSize = MAX_BLOCK_WEIGHT / WITNESS_SCALE_FACTOR;
+    const auto oversizedTransactionBaseSize = ::GetSerializeSize(TX_NO_WITNESS(createTransaction(maxTransactionSize))) - maxTransactionSize;
+
+    auto maxPayloadSize = maxTransactionSize - oversizedTransactionBaseSize;
+    {
+        TxValidationState state;
+        CheckTransaction(createTransaction(maxPayloadSize), state);
+        BOOST_CHECK(state.GetRejectReason() != "bad-txns-oversize");
+    }
+
+    maxPayloadSize += 1;
+    {
+        TxValidationState state;
+        BOOST_CHECK_MESSAGE(!CheckTransaction(createTransaction(maxPayloadSize), state), "Oversized transaction should be invalid");
+        BOOST_CHECK(state.GetRejectReason() == "bad-txns-oversize");
+    }
+}
+
 BOOST_AUTO_TEST_CASE(basic_transaction_tests)
 {
     // Random real transaction (e2769b09e784f32f62ef849763d4f45b98e07ba658647343b915ff832b110436)
@@ -615,11 +649,11 @@ BOOST_AUTO_TEST_CASE(test_witness)
     // Normal pay-to-compressed-pubkey.
     CreateCreditAndSpend(keystore, scriptPubkey1, output1, input1);
     CreateCreditAndSpend(keystore, scriptPubkey2, output2, input2);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
-    CheckWithFlag(output1, input2, 0, false);
+    CheckWithFlag(output1, input2, SCRIPT_VERIFY_NONE, false);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);
@@ -628,11 +662,11 @@ BOOST_AUTO_TEST_CASE(test_witness)
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(scriptPubkey1)), output1, input1);
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(scriptPubkey2)), output2, input2);
     ReplaceRedeemScript(input2.vin[0].scriptSig, scriptPubkey1);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
-    CheckWithFlag(output1, input2, 0, true);
+    CheckWithFlag(output1, input2, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);
@@ -640,11 +674,11 @@ BOOST_AUTO_TEST_CASE(test_witness)
     // Witness pay-to-compressed-pubkey (v0).
     CreateCreditAndSpend(keystore, destination_script_1, output1, input1);
     CreateCreditAndSpend(keystore, destination_script_2, output2, input2);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
-    CheckWithFlag(output1, input2, 0, true);
+    CheckWithFlag(output1, input2, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);
@@ -653,11 +687,11 @@ BOOST_AUTO_TEST_CASE(test_witness)
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(destination_script_1)), output1, input1);
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(destination_script_2)), output2, input2);
     ReplaceRedeemScript(input2.vin[0].scriptSig, destination_script_1);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
-    CheckWithFlag(output1, input2, 0, true);
+    CheckWithFlag(output1, input2, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);
@@ -665,11 +699,11 @@ BOOST_AUTO_TEST_CASE(test_witness)
     // Normal pay-to-uncompressed-pubkey.
     CreateCreditAndSpend(keystore, scriptPubkey1L, output1, input1);
     CreateCreditAndSpend(keystore, scriptPubkey2L, output2, input2);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
-    CheckWithFlag(output1, input2, 0, false);
+    CheckWithFlag(output1, input2, SCRIPT_VERIFY_NONE, false);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);
@@ -678,11 +712,11 @@ BOOST_AUTO_TEST_CASE(test_witness)
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(scriptPubkey1L)), output1, input1);
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(scriptPubkey2L)), output2, input2);
     ReplaceRedeemScript(input2.vin[0].scriptSig, scriptPubkey1L);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, true);
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
-    CheckWithFlag(output1, input2, 0, true);
+    CheckWithFlag(output1, input2, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH, false);
     CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);
@@ -697,19 +731,19 @@ BOOST_AUTO_TEST_CASE(test_witness)
 
     // Normal 2-of-2 multisig
     CreateCreditAndSpend(keystore, scriptMulti, output1, input1, false);
-    CheckWithFlag(output1, input1, 0, false);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, false);
     CreateCreditAndSpend(keystore2, scriptMulti, output2, input2, false);
-    CheckWithFlag(output2, input2, 0, false);
+    CheckWithFlag(output2, input2, SCRIPT_VERIFY_NONE, false);
     BOOST_CHECK(*output1 == *output2);
     UpdateInput(input1.vin[0], CombineSignatures(input1, input2, output1));
     CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
 
     // P2SH 2-of-2 multisig
     CreateCreditAndSpend(keystore, GetScriptForDestination(ScriptHash(scriptMulti)), output1, input1, false);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, false);
     CreateCreditAndSpend(keystore2, GetScriptForDestination(ScriptHash(scriptMulti)), output2, input2, false);
-    CheckWithFlag(output2, input2, 0, true);
+    CheckWithFlag(output2, input2, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output2, input2, SCRIPT_VERIFY_P2SH, false);
     BOOST_CHECK(*output1 == *output2);
     UpdateInput(input1.vin[0], CombineSignatures(input1, input2, output1));
@@ -718,10 +752,10 @@ BOOST_AUTO_TEST_CASE(test_witness)
 
     // Witness 2-of-2 multisig
     CreateCreditAndSpend(keystore, destination_script_multi, output1, input1, false);
-    CheckWithFlag(output1, input1, 0, true);
+    CheckWithFlag(output1, input1, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, false);
     CreateCreditAndSpend(keystore2, destination_script_multi, output2, input2, false);
-    CheckWithFlag(output2, input2, 0, true);
+    CheckWithFlag(output2, input2, SCRIPT_VERIFY_NONE, true);
     CheckWithFlag(output2, input2, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, false);
     BOOST_CHECK(*output1 == *output2);
     UpdateInput(input1.vin[0], CombineSignatures(input1, input2, output1));
diff --git a/test/functional/mempool_accept.py b/test/functional/mempool_accept.py
index 3d205ffa62..e1cee46839 100755
--- a/test/functional/mempool_accept.py
+++ b/test/functional/mempool_accept.py
@@ -18,6 +18,7 @@ from test_framework.messages import (
     CTxInWitness,
     CTxOut,
     MAX_BLOCK_WEIGHT,
+    WITNESS_SCALE_FACTOR,
     MAX_MONEY,
     SEQUENCE_FINAL,
     tx_from_hex,
@@ -228,7 +229,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
 
         self.log.info('A really large transaction')
         tx = tx_from_hex(raw_tx_reference)
-        tx.vin = [tx.vin[0]] * math.ceil(MAX_BLOCK_WEIGHT // 4 / len(tx.vin[0].serialize()))
+        tx.vin = [tx.vin[0]] * math.ceil((MAX_BLOCK_WEIGHT // WITNESS_SCALE_FACTOR) / len(tx.vin[0].serialize()))
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': 'bad-txns-oversize'}],
             rawtxs=[tx.serialize().hex()],