fix: Number 静态方法 ToNumber 转换、格式化方法精度/边界修复、常量属性描述符

crates/oxide_builtins/tests/number_methods_tests.rs

@@ -0,0 +1,65 @@
+use oxide_runtime_api::to_number;
+use oxide_types::value::JsValue;
+
+#[test]
+fn is_nan_nan_returns_true() {
+    assert!(to_number(JsValue::float(f64::NAN)).is_nan());
+}
+
+#[test]
+fn is_nan_number_123_returns_false() {
+    assert!(!to_number(JsValue::int(123)).is_nan());
+}
+
+#[test]
+fn is_nan_undefined_returns_true() {
+    assert!(to_number(JsValue::undefined()).is_nan());
+}
+
+#[test]
+fn is_finite_number_42_returns_true() {
+    assert!(to_number(JsValue::int(42)).is_finite());
+}
+
+#[test]
+fn is_finite_infinity_returns_false() {
+    assert!(!to_number(JsValue::float(f64::INFINITY)).is_finite());
+}
+
+#[test]
+fn is_integer_non_number_float_nan() {
+    let val = JsValue::undefined();
+    assert!(!val.is_int() && !val.is_double());
+}
+
+#[test]
+fn is_integer_int_42() {
+    let val = JsValue::int(42);
+    assert!(val.is_int());
+    let n = to_number(val);
+    assert!(n.trunc() == n && n.is_finite());
+}
+
+#[test]
+fn is_integer_double_fractional() {
+    let val = JsValue::float(42.5);
+    assert!(val.is_double());
+    let n = to_number(val);
+    assert!(!(n.trunc() == n && n.is_finite()));
+}
+
+#[test]
+fn is_safe_integer_max_value() {
+    let val = JsValue::float(9007199254740991f64);
+    let n = to_number(val);
+    assert!(n.trunc() == n && n.is_finite());
+    assert!(n >= -9007199254740991i64 as f64 && n <= 9007199254740991i64 as f64);
+}
+
+#[test]
+fn is_safe_integer_overflow() {
+    let val = JsValue::float(9007199254740992f64);
+    let n = to_number(val);
+    assert!(n.trunc() == n && n.is_finite());
+    assert!(!(n >= -9007199254740991i64 as f64 && n <= 9007199254740991i64 as f64));
+}