fix: resolve multiple_of validation bug for negative floats using round-based approach

Author: K-dash

src/validators/float.rs

@@ -109,23 +109,10 @@ impl Validator for ConstrainedFloatValidator {
             return Err(ValError::new(ErrorTypeDefaults::FiniteNumber, input));
         }
         if let Some(multiple_of) = self.multiple_of {
-            const EPSILON_FACTOR: f64 = 100.0;
-            let epsilon_threshold = f64::EPSILON * EPSILON_FACTOR;
-
-            // Round the result of dividing the input value by the multiple
-            let rounded = (float / multiple_of).round();
-
-            // Calculate the difference between the rounded value and the original value
-            let diff = (float - rounded * multiple_of).abs();
-
-            // Calculate the relative error (avoid division by zero)
-            let relative_error = if float != 0.0 { diff / float.abs() } else { 0.0 };
-
-            // Threshold (considering both relative and absolute error)
-            let threshold = epsilon_threshold.max(multiple_of * epsilon_threshold);
-
-            // Check if the difference exceeds the threshold and the relative error is significant
-            if diff > threshold && relative_error > epsilon_threshold {
+            let tolerance = 1e-9;
+            let rounded_div = (float / multiple_of).round();
+            let diff = (float - (rounded_div * multiple_of)).abs();
+            if diff > tolerance {
                 return Err(ValError::new(
                     ErrorType::MultipleOf {
                         multiple_of: multiple_of.into(),