Apply contribution guidelines to "Even" rule

Also add an extra validation to the rule, not allowing non-integers to
be considered as even numbers.

Co-Authored-By: Henrique Moody <henriquemoody@gmail.com>

docs/Even.md

@@ -2,7 +2,7 @@
 
 - `Even()`
 
-Validates an even number.
+Validates whether the input is an even number or not.
 
 ```php
 v::intVal()->even()->validate(2); // true

library/Exceptions/EvenException.php

@@ -13,8 +13,18 @@ declare(strict_types=1);
 
 namespace Respect\Validation\Exceptions;
 
-class EvenException extends ValidationException
+/**
+ * Exceptions to be thrown by the Even Rule.
+ *
+ * @author Henrique Moody <henriquemoody@gmail.com>
+ * @author Jean Pimentel <jeanfap@gmail.com>
+ * @author Paul Karikari <paulkarikari1@gmail.com>
+ */
+final class EvenException extends ValidationException
 {
+    /**
+     * {@inheritdoc}
+     */
     public static $defaultTemplates = [
         self::MODE_DEFAULT => [
             self::STANDARD => '{{name}} must be an even number',

library/Rules/Even.php

@@ -13,10 +13,27 @@ declare(strict_types=1);
 
 namespace Respect\Validation\Rules;
 
-class Even extends AbstractRule
+use const FILTER_VALIDATE_INT;
+use function filter_var;
+
+/**
+ * Validates whether the input is an even number or not.
+ *
+ * @author Henrique Moody <henriquemoody@gmail.com>
+ * @author Jean Pimentel <jeanfap@gmail.com>
+ * @author Paul Karikari <paulkarikari1@gmail.com>
+ */
+final class Even extends AbstractRule
 {
+    /**
+     * {@inheritdoc}
+     */
     public function validate($input): bool
     {
+        if (false === filter_var($input, FILTER_VALIDATE_INT)) {
+            return false;
+        }
+
         return 0 === (int) $input % 2;
     }
 }

tests/integration/rules/even.phpt

@@ -0,0 +1,38 @@
+--FILE--
+<?php
+require 'vendor/autoload.php';
+
+use Respect\Validation\Exceptions\EvenException;
+use Respect\Validation\Exceptions\NestedValidationException;
+use Respect\Validation\Validator as v;
+
+try {
+    v::even()->check(-1);
+} catch (EvenException $exception) {
+    echo $exception->getMessage().PHP_EOL;
+}
+
+try {
+    v::even()->assert(5);
+} catch (NestedValidationException $exception) {
+    echo $exception->getFullMessage().PHP_EOL;
+}
+
+try {
+    v::not(v::even())->check(6);
+} catch (EvenException $exception) {
+    echo $exception->getMessage().PHP_EOL;
+}
+
+try {
+    v::not(v::even())->assert(8);
+} catch (NestedValidationException $exception) {
+    echo $exception->getFullMessage().PHP_EOL;
+}
+
+?>
+--EXPECTF--
+-1 must be an even number
+- 5 must be an even number
+6 must not be an even number
+- 8 must not be an even number

tests/unit/Rules/EvenTest.php

@@ -13,60 +13,45 @@ declare(strict_types=1);
 
 namespace Respect\Validation\Rules;
 
-use PHPUnit\Framework\TestCase;
+use Respect\Validation\Test\RuleTestCase;
 
 /**
- * @group  rule
+ * @group rule
+ *
  * @covers \Respect\Validation\Rules\Even
- * @covers \Respect\Validation\Exceptions\EvenException
+ *
+ * @author Henrique Moody <henriquemoody@gmail.com>
+ * @author Jean Pimentel <jeanfap@gmail.com>
+ * @author Paul Karikari <paulkarikari1@gmail.com>
  */
-class EvenTest extends TestCase
+final class EvenTest extends RuleTestCase
 {
-    protected $evenValidator;
-
-    protected function setUp(): void
-    {
-        $this->evenValidator = new Even();
-    }
-
     /**
-     * @dataProvider providerForEven
+     * {@inheritdoc}
      */
-    public function testEvenNumbersShouldPass($input): void
-    {
-        self::assertTrue($this->evenValidator->validate($input));
-        $this->evenValidator->check($input);
-        $this->evenValidator->assert($input);
-    }
-
-    /**
-     * @dataProvider providerForNotEven
-     * @expectedException \Respect\Validation\Exceptions\EvenException
-     */
-    public function testNotEvenNumbersShouldFail($input): void
-    {
-        self::assertFalse($this->evenValidator->validate($input));
-        $this->evenValidator->assert($input);
-    }
-
-    public function providerForEven()
+    public function providerForValidInput(): array
     {
         return [
-            [''],
-            [-2],
-            [-0],
-            [0],
-            [32],
+            [new Even(), 2],
+            [new Even(), -2],
+            [new Even(), 0],
+            [new Even(), 32],
         ];
     }
 
-    public function providerForNotEven()
+    /**
+     * {@inheritdoc}
+     */
+    public function providerForInvalidInput(): array
     {
         return [
-            [-5],
-            [-1],
-            [1],
-            [13],
+            [new Even(), ''],
+            [new Even(), INF],
+            [new Even(), 2.2],
+            [new Even(), -5],
+            [new Even(), -1],
+            [new Even(), 1],
+            [new Even(), 13],
         ];
     }
 }