Numeric Validation Constraint

Engine.php

class Enginge {
    /**
     * @ORM\Column(type="float")
     * @Assert\NotBlank()
     * @Assert\Numeric(maxScale = 2)
     */
    private $power;
}

Idea.md

The idea is that you can enforce a max scale rather than just magically round the number to the exact scale. This is pretty useful if you do not always use the form to retrieve the data, you can validate the entity in case of automated imports or as in my use case due to an Excel import.

Numeric.php

use Symfony\Component\Validator\Constraint;

/**
 * @Annotation
 */
class Numeric extends Constraint
{
    public $maxScale = null;
    public $message = 'The number has more than {{ maxScale }} decimal places.';
}

NumericValidator.php

class NumericValidator extends ConstraintValidator
{
    /**
     * {@inheritdoc}
     */
    public function validate($value, Constraint $constraint)
    {
        if (!$constraint instanceof Numeric) {
            throw new UnexpectedTypeException($constraint, __NAMESPACE__.'\Numeric');
        }

        $maxScale = $constraint->maxScale;

        if (null === $maxScale) {
            return;
        }

        if (is_int($value)) {
            return;
        }

        // no additional type checks
        if (!is_numeric($value)) {
            return;
        }

        if (abs($value - round($value, $maxScale)) >= 0.0000000000001 ) {
            $this->context->buildViolation($constraint->message)
                ->setParameter('{{ maxScale }}', $constraint->maxScale)
                ->addViolation();
        }
    }
}

NumericValidatorTest.php

class NumericValidatorTest extends \PHPUnit_Framework_TestCase
{
    /**
     * @dataProvider getNumericData
     *
     * @param string  $string
     * @param integer $maxScale
     * @param boolean $valid
     */
    public function testMaxScale($string, $maxScale, $valid)
    {
        $context = $this->getMock(
            'Symfony\Component\Validator\ExecutionContext',
            [ 'buildViolation' ],
            [],
            '',
            false
        );

        $violationBuilder = $this->getMock(
            'Symfony\Component\Validator\Violation\ConstraintViolationBuilder',
            [ 'addViolation' ],
            [],
            '',
            false
        );

        $context->expects($valid ? $this->never() : $this->once())
            ->method('buildViolation')
            ->with('The number has more than {{ maxScale }} decimal places.')
            ->willReturn($violationBuilder);

        $violationBuilder->expects($valid ? $this->never() : $this->once())
            ->method('addViolation');

        $validator = new NumericValidator();
        $constraint = new Numeric();
        $constraint->maxScale = $maxScale;

        /** @var ExecutionContextInterface $context */
        $validator->initialize($context);
        $validator->validate($string, $constraint);
    }

    public function getNumericData()
    {
        return [
            [ 6.0795, 3, false ],
            [ 1.0001, 4, true ],
            [ 1.0001, 2, false ],
            [ 1.00, 2, true ],
            [ 1.00, 3, true ],
            [ 0.00000000000012, 4, false ],
            [ 1000000.000000001, 4, false ],
            [ 1.0001, 4, true ],
            [ 1, 4, true ],
        ];
    }
}