Function TEST

pj_scripting/tests/lua_time_precision_test.cpp:41–53

}  // namespace

TEST(LuaTimePrecision, RebasedDerivativeIsExactAtNanosecondScale) {
  auto engine = makeLuauEngine();
  auto classes = engine->inspectModule(kDerivative, "test");
  ASSERT_TRUE(classes.has_value());
  LuaSisoTransform xf(engine, classes->front(), "{}");

  // Two samples 100 ns apart, sitting at a ~2026 absolute epoch.
  (void)xf.calculateNextPoint(Sample::scalar(kEpochNs, PJ::VarValue{0.0}));
  auto out = xf.calculateNextPoint(Sample::scalar(kEpochNs + 100, PJ::VarValue{1.0}));
  ASSERT_TRUE(out.has_value());
  // dt = 100 ns = 1e-7 s, so d = 1 / 1e-7 = 1e7, exactly (rebasing keeps it).
  EXPECT_NEAR(PJ::proc::detail::toDouble(out->value()), 1e7, 1.0);
}

TEST(LuaTimePrecision, NaiveAbsoluteEpochInDoubleCollapses100nsDt) {
  // The bug the rebasing avoids: subtracting two absolute-epoch doubles.