public function assertElementAttribute($selector, $attribute, $expectedValue)
    {
        $actualValue = $this->element('*', $selector)->getAttribute($attribute);

        if (null === $actualValue) {
            throw new \InvalidArgumentException(sprintf(
                'Element does not contain the "%s" attribute.',
                $attribute
            ));
        } elseif ($actualValue !== $expectedValue) {
            throw new \Exception(sprintf(
                'Attribute "%s" have the "%s" value which is not equal to "%s".',
                $attribute,
                $actualValue,
                $expectedValue
            ));
        }
    }
public function assertElementAttribute($selector, $attribute, $expectedValue)
    {
        $actualValue = $this->element('*', $selector)->getAttribute($attribute);

        if (null === $actualValue) {
            throw new \InvalidArgumentException(sprintf(
                'Element does not contain the "%s" attribute.',
                $attribute
            ));
        } elseif ($actualValue !== $expectedValue) {
            throw new \Exception(sprintf(
                'Attribute "%s" have the "%s" value which is not equal to "%s".',
                $attribute,
                $actualValue,
                $expectedValue
            ));
        }
    }
@param string $selector
@param string $attribute
@param string $expectedValue

@throws \Exception

@example
Then I should see the "#table_cell" element with "colspan" attribute having "3" value

@Then /^(?:|I )should see the "([^"]*)" element with "([^"]*)" attribute having "([^"]*)" value$/