Files
rippled/src/test/app/LendingHelpers_test.cpp
2025-12-02 16:02:54 +01:00

643 lines
23 KiB
C++

#include <xrpl/beast/unit_test/suite.h>
// DO NOT REMOVE
#include <test/jtx.h>
#include <test/jtx/Account.h>
#include <test/jtx/amount.h>
#include <test/jtx/mpt.h>
#include <xrpld/app/misc/LendingHelpers.h>
#include <xrpld/app/misc/LoadFeeTrack.h>
#include <xrpld/app/tx/detail/Batch.h>
#include <xrpld/app/tx/detail/LoanSet.h>
#include <xrpl/beast/xor_shift_engine.h>
#include <xrpl/protocol/SField.h>
#include <string>
#include <vector>
namespace ripple {
namespace test {
class LendingHelpers_test : public beast::unit_test::suite
{
void
testComputeRaisedRate()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number periodicRate;
std::uint32_t paymentsRemaining;
Number expectedRaisedRate;
};
auto const testCases = std::vector<TestCase>{
{
.name = "Zero payments remaining",
.periodicRate = Number{5, -2},
.paymentsRemaining = 0,
.expectedRaisedRate = Number{1}, // (1 + r)^0 = 1
},
{
.name = "One payment remaining",
.periodicRate = Number{5, -2},
.paymentsRemaining = 1,
.expectedRaisedRate = Number{105, -2},
}, // 1.05^1
{
.name = "Multiple payments remaining",
.periodicRate = Number{5, -2},
.paymentsRemaining = 3,
.expectedRaisedRate = Number{1157625, -6},
}, // 1.05^3
{
.name = "Zero periodic rate",
.periodicRate = Number{0},
.paymentsRemaining = 5,
.expectedRaisedRate = Number{1}, // (1 + 0)^5 = 1
}};
for (auto const& tc : testCases)
{
testcase("computeRaisedRate: " + tc.name);
auto const computedRaisedRate =
computeRaisedRate(tc.periodicRate, tc.paymentsRemaining);
BEAST_EXPECTS(
computedRaisedRate == tc.expectedRaisedRate,
"Raised rate mismatch: expected " +
to_string(tc.expectedRaisedRate) + ", got " +
to_string(computedRaisedRate));
}
}
void
testComputePaymentFactor()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number periodicRate;
std::uint32_t paymentsRemaining;
Number expectedPaymentFactor;
};
auto const testCases = std::vector<TestCase>{
{
.name = "Zero periodic rate",
.periodicRate = Number{0},
.paymentsRemaining = 4,
.expectedPaymentFactor = Number{25, -2},
}, // 1/4 = 0.25
{
.name = "One payment remaining",
.periodicRate = Number{5, -2},
.paymentsRemaining = 1,
.expectedPaymentFactor = Number{105, -2},
}, // 0.05/1 = 1.05
{
.name = "Multiple payments remaining",
.periodicRate = Number{5, -2},
.paymentsRemaining = 3,
.expectedPaymentFactor = Number{367208564631245, -15},
}, // from calc
{
.name = "Zero payments remaining",
.periodicRate = Number{5, -2},
.paymentsRemaining = 0,
.expectedPaymentFactor = Number{0},
} // edge case
};
for (auto const& tc : testCases)
{
testcase("computePaymentFactor: " + tc.name);
auto const computedPaymentFactor =
computePaymentFactor(tc.periodicRate, tc.paymentsRemaining);
BEAST_EXPECTS(
computedPaymentFactor == tc.expectedPaymentFactor,
"Payment factor mismatch: expected " +
to_string(tc.expectedPaymentFactor) + ", got " +
to_string(computedPaymentFactor));
}
}
void
testLoanPeriodicPayment()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number principalOutstanding;
Number periodicRate;
std::uint32_t paymentsRemaining;
Number expectedPeriodicPayment;
};
auto const testCases = std::vector<TestCase>{
{
.name = "Zero principal outstanding",
.principalOutstanding = Number{0},
.periodicRate = Number{5, -2},
.paymentsRemaining = 5,
.expectedPeriodicPayment = Number{0},
},
{
.name = "Zero payments remaining",
.principalOutstanding = Number{1'000},
.periodicRate = Number{5, -2},
.paymentsRemaining = 0,
.expectedPeriodicPayment = Number{0},
},
{
.name = "Zero periodic rate",
.principalOutstanding = Number{1'000},
.periodicRate = Number{0},
.paymentsRemaining = 4,
.expectedPeriodicPayment = Number{250},
},
{
.name = "Standard case",
.principalOutstanding = Number{1'000},
.periodicRate =
loanPeriodicRate(TenthBips32(100'000), 30 * 24 * 60 * 60),
.paymentsRemaining = 3,
.expectedPeriodicPayment =
Number{3895690663961231, -13}, // from calc
},
};
for (auto const& tc : testCases)
{
testcase("loanPeriodicPayment: " + tc.name);
auto const computedPeriodicPayment = loanPeriodicPayment(
tc.principalOutstanding, tc.periodicRate, tc.paymentsRemaining);
BEAST_EXPECTS(
computedPeriodicPayment == tc.expectedPeriodicPayment,
"Periodic payment mismatch: expected " +
to_string(tc.expectedPeriodicPayment) + ", got " +
to_string(computedPeriodicPayment));
}
}
void
testLoanPrincipalFromPeriodicPayment()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number periodicPayment;
Number periodicRate;
std::uint32_t paymentsRemaining;
Number expectedPrincipalOutstanding;
};
auto const testCases = std::vector<TestCase>{
{
.name = "Zero periodic payment",
.periodicPayment = Number{0},
.periodicRate = Number{5, -2},
.paymentsRemaining = 5,
.expectedPrincipalOutstanding = Number{0},
},
{
.name = "Zero payments remaining",
.periodicPayment = Number{1'000},
.periodicRate = Number{5, -2},
.paymentsRemaining = 0,
.expectedPrincipalOutstanding = Number{0},
},
{
.name = "Zero periodic rate",
.periodicPayment = Number{250},
.periodicRate = Number{0},
.paymentsRemaining = 4,
.expectedPrincipalOutstanding = Number{1'000},
},
{
.name = "Standard case",
.periodicPayment = Number{3895690663961231, -13}, // from calc
.periodicRate =
loanPeriodicRate(TenthBips32(100'000), 30 * 24 * 60 * 60),
.paymentsRemaining = 3,
.expectedPrincipalOutstanding = Number{1'000},
},
};
for (auto const& tc : testCases)
{
testcase("loanPrincipalFromPeriodicPayment: " + tc.name);
auto const computedPrincipalOutstanding =
loanPrincipalFromPeriodicPayment(
tc.periodicPayment, tc.periodicRate, tc.paymentsRemaining);
BEAST_EXPECTS(
computedPrincipalOutstanding == tc.expectedPrincipalOutstanding,
"Principal outstanding mismatch: expected " +
to_string(tc.expectedPrincipalOutstanding) + ", got " +
to_string(computedPrincipalOutstanding));
}
}
void
testComputeOverpaymentComponents()
{
testcase("computeOverpaymentComponents");
using namespace jtx;
using namespace ripple::detail;
Account const issuer{"issuer"};
PrettyAsset const IOU = issuer["IOU"];
int32_t const loanScale = 1;
auto const overpayment = Number{1'000};
auto const overpaymentInterestRate = TenthBips32{10'000}; // 10%
auto const overpaymentFeeRate = TenthBips32{50'000}; // 50%
auto const managementFeeRate = TenthBips16{10'000}; // 10%
auto const expectedOverpaymentFee = Number{500}; // 50% of 1,000
auto const expectedOverpaymentInterestGross =
Number{100}; // 10% of 1,000
auto const expectedOverpaymentInterestNet =
Number{90}; // 100 - 10% of 100
auto const expectedOverpaymentManagementFee = Number{10}; // 10% of 100
auto const expectedPrincipalPortion = Number{400}; // 1,000 - 100 - 500
auto const components = detail::computeOverpaymentComponents(
IOU,
loanScale,
overpayment,
overpaymentInterestRate,
overpaymentFeeRate,
managementFeeRate);
BEAST_EXPECT(
components.untrackedManagementFee == expectedOverpaymentFee);
BEAST_EXPECT(
components.untrackedInterest == expectedOverpaymentInterestNet);
BEAST_EXPECT(
components.trackedManagementFeeDelta ==
expectedOverpaymentManagementFee);
BEAST_EXPECT(
components.trackedPrincipalDelta == expectedPrincipalPortion);
BEAST_EXPECT(
components.trackedManagementFeeDelta +
components.untrackedInterest ==
expectedOverpaymentInterestGross);
BEAST_EXPECT(
components.trackedManagementFeeDelta +
components.untrackedInterest +
components.trackedPrincipalDelta +
components.untrackedManagementFee ==
overpayment);
}
void
testComputeInterestAndFeeParts()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number interest;
TenthBips16 managementFeeRate;
Number expectedInterestPart;
Number expectedFeePart;
};
Account const issuer{"issuer"};
PrettyAsset const IOU = issuer["IOU"];
std::int32_t const loanScale = 1;
auto const testCases = std::vector<TestCase>{
{.name = "Zero interest",
.interest = Number{0},
.managementFeeRate = TenthBips16{10'000},
.expectedInterestPart = Number{0},
.expectedFeePart = Number{0}},
{.name = "Zero fee rate",
.interest = Number{1'000},
.managementFeeRate = TenthBips16{0},
.expectedInterestPart = Number{1'000},
.expectedFeePart = Number{0}},
{.name = "10% fee rate",
.interest = Number{1'000},
.managementFeeRate = TenthBips16{10'000},
.expectedInterestPart = Number{900},
.expectedFeePart = Number{100}},
};
for (auto const& tc : testCases)
{
testcase("computeInterestAndFeeParts: " + tc.name);
auto const [computedInterestPart, computedFeePart] =
computeInterestAndFeeParts(
IOU, tc.interest, tc.managementFeeRate, loanScale);
BEAST_EXPECTS(
computedInterestPart == tc.expectedInterestPart,
"Interest part mismatch: expected " +
to_string(tc.expectedInterestPart) + ", got " +
to_string(computedInterestPart));
BEAST_EXPECTS(
computedFeePart == tc.expectedFeePart,
"Fee part mismatch: expected " + to_string(tc.expectedFeePart) +
", got " + to_string(computedFeePart));
}
}
void
testLoanLatePaymentInterest()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number principalOutstanding;
TenthBips32 lateInterestRate;
NetClock::time_point parentCloseTime;
std::uint32_t nextPaymentDueDate;
Number expectedLateInterest;
};
auto const testCases = std::vector<TestCase>{
{
.name = "On-time payment",
.principalOutstanding = Number{1'000},
.lateInterestRate = TenthBips32{10'000}, // 10%
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.nextPaymentDueDate = 3'000,
.expectedLateInterest = Number{0},
},
{
.name = "Early payment",
.principalOutstanding = Number{1'000},
.lateInterestRate = TenthBips32{10'000}, // 10%
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.nextPaymentDueDate = 4'000,
.expectedLateInterest = Number{0},
},
{
.name = "No principal outstanding",
.principalOutstanding = Number{0},
.lateInterestRate = TenthBips32{10'000}, // 10%
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.nextPaymentDueDate = 2'000,
.expectedLateInterest = Number{0},
},
{
.name = "No late interest rate",
.principalOutstanding = Number{1'000},
.lateInterestRate = TenthBips32{0}, // 0%
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.nextPaymentDueDate = 2'000,
.expectedLateInterest = Number{0},
},
{
.name = "Late payment",
.principalOutstanding = Number{1'000},
.lateInterestRate = TenthBips32{100'000}, // 100%
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.nextPaymentDueDate = 2'000,
.expectedLateInterest =
Number{3170979198376459, -17}, // from calc
},
};
for (auto const& tc : testCases)
{
testcase("loanLatePaymentInterest: " + tc.name);
auto const computedLateInterest = loanLatePaymentInterest(
tc.principalOutstanding,
tc.lateInterestRate,
tc.parentCloseTime,
tc.nextPaymentDueDate);
BEAST_EXPECTS(
computedLateInterest == tc.expectedLateInterest,
"Late interest mismatch: expected " +
to_string(tc.expectedLateInterest) + ", got " +
to_string(computedLateInterest));
}
}
void
testLoanAccruedInterest()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number principalOutstanding;
Number periodicRate;
NetClock::time_point parentCloseTime;
std::uint32_t startDate;
std::uint32_t prevPaymentDate;
std::uint32_t paymentInterval;
Number expectedAccruedInterest;
};
auto const testCases = std::vector<TestCase>{
{
.name = "Zero principal outstanding",
.principalOutstanding = Number{0},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.startDate = 2'000,
.prevPaymentDate = 2'500,
.paymentInterval = 30 * 24 * 60 * 60,
.expectedAccruedInterest = Number{0},
},
{
.name = "Before start date",
.principalOutstanding = Number{1'000},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{1'000}},
.startDate = 2'000,
.prevPaymentDate = 1'500,
.paymentInterval = 30 * 24 * 60 * 60,
.expectedAccruedInterest = Number{0},
},
{
.name = "Zero periodic rate",
.principalOutstanding = Number{1'000},
.periodicRate = Number{0},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.startDate = 2'000,
.prevPaymentDate = 2'500,
.paymentInterval = 30 * 24 * 60 * 60,
.expectedAccruedInterest = Number{0},
},
{
.name = "Zero payment interval",
.principalOutstanding = Number{1'000},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.startDate = 2'000,
.prevPaymentDate = 2'500,
.paymentInterval = 0,
.expectedAccruedInterest = Number{0},
},
{
.name = "Standard case",
.principalOutstanding = Number{1'000},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.startDate = 1'000,
.prevPaymentDate = 2'000,
.paymentInterval = 30 * 24 * 60 * 60,
.expectedAccruedInterest =
Number{1929012345679012, -17}, // from calc
},
};
for (auto const& tc : testCases)
{
testcase("loanAccruedInterest: " + tc.name);
auto const computedAccruedInterest = loanAccruedInterest(
tc.principalOutstanding,
tc.periodicRate,
tc.parentCloseTime,
tc.startDate,
tc.prevPaymentDate,
tc.paymentInterval);
BEAST_EXPECTS(
computedAccruedInterest == tc.expectedAccruedInterest,
"Accrued interest mismatch: expected " +
to_string(tc.expectedAccruedInterest) + ", got " +
to_string(computedAccruedInterest));
}
}
// This test overlaps with testLoanAccruedInterest, the test cases only
// exercise the computeFullPaymentInterest parts unique to it.
void
testComputeFullPaymentInterest()
{
using namespace jtx;
using namespace ripple::detail;
struct TestCase
{
std::string name;
Number rawPrincipalOutstanding;
Number periodicRate;
NetClock::time_point parentCloseTime;
std::uint32_t paymentInterval;
std::uint32_t prevPaymentDate;
std::uint32_t startDate;
TenthBips32 closeInterestRate;
Number expectedFullPaymentInterest;
};
auto const testCases = std::vector<TestCase>{
{
.name = "Zero principal outstanding",
.rawPrincipalOutstanding = Number{0},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.paymentInterval = 30 * 24 * 60 * 60,
.prevPaymentDate = 2'000,
.startDate = 1'000,
.closeInterestRate = TenthBips32{10'000},
.expectedFullPaymentInterest = Number{0},
},
{
.name = "Zero close interest rate",
.rawPrincipalOutstanding = Number{1'000},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.paymentInterval = 30 * 24 * 60 * 60,
.prevPaymentDate = 2'000,
.startDate = 1'000,
.closeInterestRate = TenthBips32{0},
.expectedFullPaymentInterest =
Number{1929012345679012, -17}, // from calc
},
{
.name = "Standard case",
.rawPrincipalOutstanding = Number{1'000},
.periodicRate = Number{5, -2},
.parentCloseTime =
NetClock::time_point{NetClock::duration{3'000}},
.paymentInterval = 30 * 24 * 60 * 60,
.prevPaymentDate = 2'000,
.startDate = 1'000,
.closeInterestRate = TenthBips32{10'000},
.expectedFullPaymentInterest =
Number{1000192901234568, -13}, // from calc
},
};
for (auto const& tc : testCases)
{
testcase("computeFullPaymentInterest: " + tc.name);
auto const computedFullPaymentInterest = computeFullPaymentInterest(
tc.rawPrincipalOutstanding,
tc.periodicRate,
tc.parentCloseTime,
tc.paymentInterval,
tc.prevPaymentDate,
tc.startDate,
tc.closeInterestRate);
BEAST_EXPECTS(
computedFullPaymentInterest == tc.expectedFullPaymentInterest,
"Full payment interest mismatch: expected " +
to_string(tc.expectedFullPaymentInterest) + ", got " +
to_string(computedFullPaymentInterest));
}
}
public:
void
run() override
{
testComputeFullPaymentInterest();
testLoanAccruedInterest();
testLoanLatePaymentInterest();
testLoanPeriodicPayment();
testLoanPrincipalFromPeriodicPayment();
testComputeRaisedRate();
testComputePaymentFactor();
testComputeOverpaymentComponents();
testComputeInterestAndFeeParts();
}
};
BEAST_DEFINE_TESTSUITE(LendingHelpers, app, ripple);
} // namespace test
} // namespace ripple