diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index f87779a4780..35d8fe129f7 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -20,6 +20,7 @@
 #include <script/signingprovider.h>
 #include <script/standard.h>
 #include <streams.h>
+#include <test/util/script.h>
 #include <test/util/transaction_utils.h>
 #include <util/strencodings.h>
 #include <util/string.h>
@@ -59,6 +60,9 @@ static std::map<std::string, unsigned int> mapFlagNames = {
     {std::string("WITNESS_PUBKEYTYPE"), (unsigned int)SCRIPT_VERIFY_WITNESS_PUBKEYTYPE},
     {std::string("CONST_SCRIPTCODE"), (unsigned int)SCRIPT_VERIFY_CONST_SCRIPTCODE},
     {std::string("TAPROOT"), (unsigned int)SCRIPT_VERIFY_TAPROOT},
+    {std::string("DISCOURAGE_UPGRADABLE_PUBKEYTYPE"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE},
+    {std::string("DISCOURAGE_OP_SUCCESS"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS},
+    {std::string("DISCOURAGE_UPGRADABLE_TAPROOT_VERSION"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION},
 };
 
 unsigned int ParseScriptFlags(std::string strFlags)
@@ -139,6 +143,7 @@ unsigned int TrimFlags(unsigned int flags)
 
     // CLEANSTACK requires WITNESS (and transitively CLEANSTACK requires P2SH)
     if (!(flags & SCRIPT_VERIFY_WITNESS)) flags &= ~(unsigned int)SCRIPT_VERIFY_CLEANSTACK;
+    Assert(IsValidFlagCombination(flags));
     return flags;
 }
 
@@ -149,6 +154,7 @@ unsigned int FillFlags(unsigned int flags)
 
     // WITNESS implies P2SH (and transitively CLEANSTACK implies P2SH)
     if (flags & SCRIPT_VERIFY_WITNESS) flags |= SCRIPT_VERIFY_P2SH;
+    Assert(IsValidFlagCombination(flags));
     return flags;
 }
 
@@ -231,16 +237,15 @@ BOOST_AUTO_TEST_CASE(tx_valid)
                 BOOST_ERROR("Bad test flags: " << strTest);
             }
 
-            if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, ~verify_flags, txdata, strTest, /* expect_valid */ true)) {
-                BOOST_ERROR("Tx unexpectedly failed: " << strTest);
-            }
+            BOOST_CHECK_MESSAGE(CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, ~verify_flags, txdata, strTest, /* expect_valid */ true),
+                                "Tx unexpectedly failed: " << strTest);
 
             // Backwards compatibility of script verification flags: Removing any flag(s) should not invalidate a valid transaction
-            for (size_t i = 0; i < mapFlagNames.size(); ++i) {
+            for (const auto& [name, flag] : mapFlagNames) {
                 // Removing individual flags
-                unsigned int flags = TrimFlags(~(verify_flags | (1U << i)));
+                unsigned int flags = TrimFlags(~(verify_flags | flag));
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /* expect_valid */ true)) {
-                    BOOST_ERROR("Tx unexpectedly failed with flag " << ToString(i) << " unset: " << strTest);
+                    BOOST_ERROR("Tx unexpectedly failed with flag " << name << " unset: " << strTest);
                 }
                 // Removing random combinations of flags
                 flags = TrimFlags(~(verify_flags | (unsigned int)InsecureRandBits(mapFlagNames.size())));
@@ -250,7 +255,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
             }
 
             // Check that flags are maximal: transaction should fail if any unset flags are set.
-            for (auto flags_excluding_one: ExcludeIndividualFlags(verify_flags)) {
+            for (auto flags_excluding_one : ExcludeIndividualFlags(verify_flags)) {
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, ~flags_excluding_one, txdata, strTest, /* expect_valid */ false)) {
                     BOOST_ERROR("Too many flags unset: " << strTest);
                 }
@@ -317,27 +322,31 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
             PrecomputedTransactionData txdata(tx);
             unsigned int verify_flags = ParseScriptFlags(test[2].get_str());
 
-            // Not using FillFlags() in the main test, in order to detect invalid verifyFlags combination
-            if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, verify_flags, txdata, strTest, /* expect_valid */ false)) {
-                BOOST_ERROR("Tx unexpectedly passed: " << strTest);
+            // Check that the test gives a valid combination of flags (otherwise VerifyScript will throw). Don't edit the flags.
+            if (verify_flags != FillFlags(verify_flags)) {
+                BOOST_ERROR("Bad test flags: " << strTest);
             }
 
+            // Not using FillFlags() in the main test, in order to detect invalid verifyFlags combination
+            BOOST_CHECK_MESSAGE(CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, verify_flags, txdata, strTest, /* expect_valid */ false),
+                                "Tx unexpectedly passed: " << strTest);
+
             // Backwards compatibility of script verification flags: Adding any flag(s) should not validate an invalid transaction
-            for (size_t i = 0; i < mapFlagNames.size(); i++) {
-                unsigned int flags = FillFlags(verify_flags | (1U << i));
+            for (const auto& [name, flag] : mapFlagNames) {
+                unsigned int flags = FillFlags(verify_flags | flag);
                 // Adding individual flags
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /* expect_valid */ false)) {
-                    BOOST_ERROR("Tx unexpectedly passed with flag " << ToString(i) << " set: " << strTest);
+                    BOOST_ERROR("Tx unexpectedly passed with flag " << name << " set: " << strTest);
                 }
                 // Adding random combinations of flags
                 flags = FillFlags(verify_flags | (unsigned int)InsecureRandBits(mapFlagNames.size()));
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /* expect_valid */ false)) {
-                    BOOST_ERROR("Tx unexpectedly passed with random flags " << ToString(flags) << ": " << strTest);
+                    BOOST_ERROR("Tx unexpectedly passed with random flags " << name << ": " << strTest);
                 }
             }
 
             // Check that flags are minimal: transaction should succeed if any set flags are unset.
-            for (auto flags_excluding_one: ExcludeIndividualFlags(verify_flags)) {
+            for (auto flags_excluding_one : ExcludeIndividualFlags(verify_flags)) {
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags_excluding_one, txdata, strTest, /* expect_valid */ true)) {
                     BOOST_ERROR("Too many flags set: " << strTest);
                 }