Add unit tests for normalizeToRange

- Steal changes from @pratik's #6150 to avoid UB
This commit is contained in:
Ed Hennis
2026-01-28 17:28:27 -05:00
parent e464adaee6
commit f7b6834d2a
4 changed files with 229 additions and 16 deletions

View File

@@ -1884,6 +1884,206 @@ public:
}
}
void
testNormalizeToRange()
{
// Test edge-cases of normalizeToRange
auto const scale = Number::getMantissaScale();
testcase << "normalizeToRange " << to_string(scale);
auto test = [this](
Number const& n,
auto const rangeMin,
auto const rangeMax,
auto const expectedMantissa,
auto const expectedExponent,
auto const line) {
auto const normalized = n.normalizeToRange(rangeMin, rangeMax);
BEAST_EXPECTS(
normalized.first == expectedMantissa,
"Number " + to_string(n) + " scaled to " +
std::to_string(rangeMax) +
". Expected mantissa:" + std::to_string(expectedMantissa) +
", got: " + std::to_string(normalized.first) + " @ " +
std::to_string(line));
BEAST_EXPECTS(
normalized.second == expectedExponent,
"Number " + to_string(n) + " scaled to " +
std::to_string(rangeMax) +
". Expected exponent:" + std::to_string(expectedExponent) +
", got: " + std::to_string(normalized.second) + " @ " +
std::to_string(line));
};
std::int64_t constexpr iRangeMin = 100;
std::int64_t constexpr iRangeMax = 999;
std::uint64_t constexpr uRangeMin = 100;
std::uint64_t constexpr uRangeMax = 999;
constexpr static MantissaRange largeRange{MantissaRange::large};
std::int64_t constexpr iBigMin = largeRange.min;
std::int64_t constexpr iBigMax = largeRange.max;
auto const testSuite = [&](Number const& n,
auto const expectedSmallMantissa,
auto const expectedSmallExponent,
auto const expectedLargeMantissa,
auto const expectedLargeExponent,
auto const line) {
test(
n,
iRangeMin,
iRangeMax,
expectedSmallMantissa,
expectedSmallExponent,
line);
test(
n,
iBigMin,
iBigMax,
expectedLargeMantissa,
expectedLargeExponent,
line);
// Only test non-negative. testing a negative number with an
// unsigned range will assert, and asserts can't be tested.
if (n.signum() >= 0)
{
test(
n,
uRangeMin,
uRangeMax,
expectedSmallMantissa,
expectedSmallExponent,
line);
test(
n,
largeRange.min,
largeRange.max,
expectedLargeMantissa,
expectedLargeExponent,
line);
}
};
{
// zero
Number const n{0};
testSuite(
n,
0,
std::numeric_limits<int>::lowest(),
0,
std::numeric_limits<int>::lowest(),
__LINE__);
}
{
// Small positive number
Number const n{2};
testSuite(n, 200, -2, 2'000'000'000'000'000'000, -18, __LINE__);
}
{
// Negative number
Number const n{-2};
testSuite(n, -200, -2, -2'000'000'000'000'000'000, -18, __LINE__);
}
{
// Biggest valid mantissa
Number const n{Number::largestMantissa, 0, Number::normalized{}};
if (scale == MantissaRange::small)
// With the small mantissa range, the value rounds up. Because
// it rounds up, when scaling up to the full int64 range, it
// can't go over the max, so it is one digit smaller than the
// full value.
testSuite(n, 922, 16, 922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, 922, 16, Number::largestMantissa, 0, __LINE__);
}
{
// Biggest valid mantissa + 1
Number const n{
Number::largestMantissa + 1, 0, Number::normalized{}};
if (scale == MantissaRange::small)
// With the small mantissa range, the value rounds up. Because
// it rounds up, when scaling up to the full int64 range, it
// can't go over the max, so it is one digit smaller than the
// full value.
testSuite(n, 922, 16, 922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, 922, 16, 922'337'203'685'477'581, 1, __LINE__);
}
{
// Biggest valid mantissa + 2
Number const n{
Number::largestMantissa + 2, 0, Number::normalized{}};
if (scale == MantissaRange::small)
// With the small mantissa range, the value rounds up. Because
// it rounds up, when scaling up to the full int64 range, it
// can't go over the max, so it is one digit smaller than the
// full value.
testSuite(n, 922, 16, 922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, 922, 16, 922'337'203'685'477'581, 1, __LINE__);
}
{
// Biggest valid mantissa + 3
Number const n{
Number::largestMantissa + 3, 0, Number::normalized{}};
if (scale == MantissaRange::small)
// With the small mantissa range, the value rounds up. Because
// it rounds up, when scaling up to the full int64 range, it
// can't go over the max, so it is one digit smaller than the
// full value.
testSuite(n, 922, 16, 922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, 922, 16, 922'337'203'685'477'581, 1, __LINE__);
}
{
// int64 min
Number const n{std::numeric_limits<std::int64_t>::min(), 0};
if (scale == MantissaRange::small)
testSuite(n, -922, 16, -922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, -922, 16, -922'337'203'685'477'581, 1, __LINE__);
}
{
// int64 min + 1
Number const n{std::numeric_limits<std::int64_t>::min() + 1, 0};
if (scale == MantissaRange::small)
testSuite(n, -922, 16, -922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, -922, 16, -9'223'372'036'854'775'807, 0, __LINE__);
}
{
// int64 min - 1
// Need to cast to uint, even though we're dealing with a negative
// number to avoid overflow and UB
Number const n{
true,
-static_cast<std::uint64_t>(
std::numeric_limits<std::int64_t>::min()) +
1,
0,
Number::normalized{}};
if (scale == MantissaRange::small)
testSuite(n, -922, 16, -922'337'203'685'477'600, 1, __LINE__);
else
testSuite(n, -922, 16, -922'337'203'685'477'581, 1, __LINE__);
}
}
void
run() override
{
@@ -1911,6 +2111,7 @@ public:
test_truncate();
testRounding();
testInt64();
testNormalizeToRange();
}
}
};