add test framework

Builds/CMake/RippledCore.cmake

@@ -749,6 +749,7 @@ if (tests)
     src/test/app/Regression_test.cpp
     src/test/app/Remit_test.cpp
     src/test/app/SHAMapStore_test.cpp
+    src/test/app/ServiceFee_test.cpp
     src/test/app/SetAuth_test.cpp
     src/test/app/SetRegularKey_test.cpp
     src/test/app/SetTrust_test.cpp

src/ripple/protocol/jss.h

@@ -126,6 +126,7 @@ JSS(UNLReport);                // transaction type.
 JSS(SettleDelay);              // in: TransactionSign
 JSS(SendMax);                  // in: TransactionSign
 JSS(Sequence);                 // in/out: TransactionSign; field.
+JSS(ServiceFee);               // field.
 JSS(SetFlag);                  // field.
 JSS(SetRegularKey);            // transaction type.
 JSS(SetHook);                  // transaction type.

src/test/app/ServiceFee_test.cpp

@@ -0,0 +1,90 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2025 XRPL-Labs
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <ripple/basics/chrono.h>
+#include <ripple/protocol/Feature.h>
+#include <ripple/protocol/jss.h>
+#include <test/jtx.h>
+
+#include <chrono>
+
+namespace ripple {
+namespace test {
+struct ServiceFee_test : public beast::unit_test::suite
+{
+    void
+    testEnabled(FeatureBitset features)
+    {
+        testcase("enabled");
+        using namespace jtx;
+        using namespace std::literals::chrono_literals;
+
+        auto const alice = Account("alice");
+        auto const bob = Account("bob");
+        auto const carol = Account("carol");
+        for (bool const withSFee : {true, false})
+        {
+            auto const amend =
+                withSFee ? features : features - featureServiceFee;
+            Env env{*this, amend};
+            auto const feeDrops = env.current()->fees().base;
+            env.fund(XRP(1000), alice, bob, carol);
+
+            auto const preAlice = env.balance(alice);
+            auto const preBob = env.balance(bob);
+            auto const preCarol = env.balance(carol);
+
+            env(pay(alice, bob, XRP(10)),
+                fee(feeDrops),
+                sfee(XRP(1), carol),
+                ter(tesSUCCESS));
+            env.close();
+
+            auto const postAlice = withSFee
+                ? preAlice - feeDrops - XRP(10) - XRP(1)
+                : preAlice - feeDrops - XRP(10);
+            auto const postBob = preBob + XRP(10);
+            auto const postCarol = withSFee ? preCarol + XRP(1) : preCarol;
+            BEAST_EXPECT(env.balance(alice) == postAlice);
+            BEAST_EXPECT(env.balance(bob) == postBob);
+            BEAST_EXPECT(env.balance(carol) == postCarol);
+        }
+    }
+
+    void
+    testWithFeats(FeatureBitset features)
+    {
+        // testEnabled();
+    }
+
+public:
+    void
+    run() override
+    {
+        using namespace test::jtx;
+        auto const sa = supported_amendments();
+        testEnabled(sa);
+        // testWithFeats(sa - featureServiceFee);
+        // testWithFeats(sa);
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(ServiceFee, app, ripple);
+}  // namespace test
+}  // namespace ripple

src/test/jtx/fee.h

@@ -61,6 +61,25 @@ public:
     operator()(Env&, JTx& jt) const;
 };
 
+/** Set the service fee on a JTx. */
+class sfee
+{
+private:
+    STAmount amount_;
+    Account dest_;
+
+public:
+    explicit sfee(
+        STAmount const& amount,
+        Account const& destination)
+        : amount_(amount), dest_(destination)
+    {
+    }
+
+    void
+    operator()(Env&, JTx& jtx) const;
+};
+
 }  // namespace jtx
 }  // namespace test
 }  // namespace ripple

src/test/jtx/impl/fee.cpp

@@ -34,6 +34,14 @@ fee::operator()(Env&, JTx& jt) const
         jt[jss::Fee] = amount_->getJson(JsonOptions::none);
 }
 
+void
+sfee::operator()(Env&, JTx& jt) const
+{
+    jt.jv[jss::ServiceFee] = Json::objectValue;
+    jt.jv[jss::ServiceFee][jss::Amount] = amount_.getJson(JsonOptions::none);
+    jt.jv[jss::ServiceFee][jss::Destination] = dest_.human();
+}
+
 }  // namespace jtx
 }  // namespace test
 }  // namespace ripple