Added hex-color rule (#19)

* created rule

* added test

* added 3 and 8 digit hex codes

* updated read me

README.md

@@ -88,6 +88,7 @@ The following validation rules are currently available:
 | CitizenIdentification | validation.citizen_identification | Requires that the given value be a citizen identification number of USA, UK, France or Brazil (see class for details) |
 | WithoutWhitespace     | validation.without_whitespace     | Requires that the given value not include any whitespace characters                                                   |
 | MaxWords              | validation.max_words              | Requires that the given value cannot contain more words than specified                                                |
+| HexColor              | validation.hex_color              | Requires that the given value is a valid hex color eg. #fff, #0f0f0f, #00ff0080                                       |
 
 ## Contributing
 
@@ -99,4 +100,4 @@ If you'd like to support the development of Axiom, then please consider [sponsor
 
 ## License
 
-The MIT License (MIT). Please see [License File](LICENSE.md) for more information.
+The MIT License (MIT). Please see [License File](LICENSE.md) for more information.

src/Rules/HexColor.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Axiom\Rules;
+
+use Axiom\Types\Rule;
+
+class HexColor extends Rule
+{
+    /**
+     * Hex color regex formats.
+     *
+     * @var array
+     */
+    private array $formats = [
+        4 => '/^#([a-fA-F0-9]{3})$/i',
+        7 => '/^#([a-fA-F0-9]{6})$/i',
+        9 => '/^#([a-fA-F0-9]{6}[0-9]{2})$/i',
+    ];
+
+    /**
+     * Determines if the rule passes.
+     *
+     * @param string $attribute
+     * @param mixed $value
+     *
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        if (! is_string($value) || ! in_array(strlen($value), array_keys($this->formats))) {
+            return false;
+        }
+
+        $match = preg_match($this->formats[strlen($value)], $value);
+
+        return $match > 0;
+    }
+
+    /**
+     * Message returned on validation failure.
+     *
+     * @return array|string
+     */
+    public function message()
+    {
+        return $this->getLocalizedErrorMessage(
+            'hex_color',
+            'The :attribute has to be a valid hex color.'
+        );
+    }
+}

tests/HexColorTest.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Axiom\Rules\Tests;
+
+use Axiom\Rules\HexColor;
+use Orchestra\Testbench\TestCase;
+
+class HexColorTest extends TestCase
+{
+    /** @test */
+    public function it_can_validate_hex_color()
+    {
+        $rule = ['hex_color' => [new HexColor()]];
+
+        $this->assertTrue(validator(['hex_color' => '#f0f0f0'], $rule)->passes());
+        $this->assertTrue(validator(['hex_color' => '#fff'], $rule)->passes());
+        $this->assertTrue(validator(['hex_color' => '#00ff0080'], $rule)->passes());
+        $this->assertFalse(validator(['hex_color' => '#00ff00ff'], $rule)->passes());
+        $this->assertFalse(validator(['hex_color' => 'f0f0f0'], $rule)->passes());
+        $this->assertFalse(validator(['hex_color' => 'rgb(0,0,255)'], $rule)->passes());
+        $this->assertTrue(validator(['hex_color' => '#000000'], $rule)->passes());
+        $this->assertFalse(validator(['hex_color' => '#0f0f'], $rule)->passes());
+    }
+}