Fix wrong behavior of "Date" rule

The validation was considering "99" as a valid month and neither
date_parse_from_format() [1] or DateTime::createFromFormat() [2] would
complain about that.

The solution for that was to use checkdate() [3] to verify whether the
date is valid or not. Also, an extra step was added to the validation
that a date that only contains a day would return false since a day
without a month and year is impossible to validate.

Apparently, there is no problem while validation when it comes to time,
therefore nothing needed to be added for this validation.

[1]: http://php.net/date_parse_from_format
[2]: http://php.net/datetime.createFromFormat
[3]: http://php.net/checkdate

Signed-off-by: Henrique Moody <henriquemoody@gmail.com>

library/Rules/Date.php

@@ -49,8 +49,39 @@ class Date extends AbstractRule
             $this->format = $exceptionalFormats[$this->format];
         }
 
-        $info = date_parse_from_format($this->format, $inputString);
+        return $this->isValidForFormatProvided($input);
+    }
 
+    private function isValidForFormatProvided($input)
+    {
+        $info = date_parse_from_format($this->format, $input);
+        if (!$this->isParsable($info)) {
+            return false;
+        }
+
+        if ($this->hasDateFormat()) {
+            return $this->hasValidDate($info);
+        }
+
+        return true;
+    }
+
+    private function isParsable(array $info)
+    {
         return ($info['error_count'] === 0 && $info['warning_count'] === 0);
     }
+
+    private function hasDateFormat()
+    {
+        return preg_match('/[djSFmMnYy]/', $this->format) > 0;
+    }
+
+    private function hasValidDate(array $info)
+    {
+        if ($info['day']) {
+            return checkdate((int) $info['month'], $info['day'], (int) $info['year']);
+        }
+
+        return checkdate($info['month'] ?: 1, $info['day'] ?: 1, $info['year'] ?: 1);
+    }
 }

tests/unit/Rules/DateTest.php

@@ -19,7 +19,7 @@ use DateTimeImmutable;
  * @covers Respect\Validation\Rules\Date
  * @covers Respect\Validation\Exceptions\DateException
  */
-class DateTest extends \PHPUnit_Framework_TestCase
+class DateTest extends RuleTestCase
 {
     protected $dateValidator;
 
@@ -150,4 +150,57 @@ class DateTest extends \PHPUnit_Framework_TestCase
                 ['UTC', 'z', 320],
         ];
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function providerForValidInput()
+    {
+        return [
+            [new Date(), 'now'],
+            [new Date(), 'today'],
+            [new Date(), 'tomorrow'],
+            [new Date(), 'yesterday'],
+            [new Date(), '+1 day'],
+            [new Date(), 'next Thursday'],
+            [new Date(), '+1 week 2 days 4 hours 2 seconds'],
+            [new Date(), 2018],
+            [new Date(), new DateTime()],
+            [new Date('Y-m-d'), '2009-09-09'],
+            [new Date('d/m/Y'), '23/05/1987'],
+            [new Date('c'), '2004-02-12T15:19:21+00:00'],
+            [new Date('r'), 'Thu, 29 Dec 2005 01:02:03 +0000'],
+            [new Date('U'), 1464658596],
+            [new Date('h'), 6],
+            [new Date('z'), 320],
+            [new Date('Ym'), 202302],
+            [new Date('m'), 12],
+            [new Date('Y'), 2000],
+        ];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function providerForInvalidInput()
+    {
+        return [
+            [new Date(), 'not-a-date'],
+            [new Date(), []],
+            [new Date(), true],
+            [new Date(), false],
+            [new Date(), null],
+            [new Date(), ''],
+            [new Date('Y-m-d'), '2009-12-00'],
+            [new Date('Y-m-d'), '2018-02-29'],
+            [new Date('h'), 24],
+            [new Date(), '2014-99'],
+            [new Date('d'), 1],
+            [new Date('Y-m'), '2014-99'],
+            [new Date('m'), '99'],
+            [new Date('H'), '24'],
+            [new Date('i'), '60'],
+            [new Date('s'), '60'],
+        ];
+    }
 }