Add test

Author: martijn00

test/src/numeric/float_validator_test.dart

@@ -67,6 +67,18 @@ void main() {
         expect(result, isNull);
       });
 
+      test('should return null if the value is a valid int', () {
+        // Arrange
+        const FloatValidator<num> validator = FloatValidator<num>();
+        const int value = 5;
+
+        // Act
+        final String? result = validator.validate(value);
+
+        // Assert
+        expect(result, isNull);
+      });
+
       test('should return error if the value is not a valid float', () {
         // Arrange
         const FloatValidator<String> validator = FloatValidator<String>();