Create "Fibonacci" rule

docs/Fibonacci.md

@@ -0,0 +1,17 @@
+# Fibonacci
+
+ - `v::fibonacci()`
+
+Validates whether the input follows the Fibonacci integer sequence.
+
+```php
+v::fibonacci()->validate(1); // true
+v::fibonacci()->validate('34'); // true
+v::fibonacci()->validate(6); // false
+```
+
+***
+See also:
+
+  * [PrimeNumber](PrimeNumber.md)
+  * [PerfectSquare](PerfectSquare.md)

docs/VALIDATORS.md

@@ -52,6 +52,7 @@
   * [BoolType](BoolType.md)
   * [Even](Even.md)
   * [Factor](Factor.md)
+  * [Fibonacci](Fibonacci.md)
   * [Finite](Finite.md)
   * [FloatVal](FloatVal.md)
   * [FloatType](FloatType.md)
@@ -238,6 +239,7 @@
   * [Extension](Extension.md)
   * [Factor](Factor.md)
   * [FalseVal](FalseVal.md)
+  * [Fibonacci](Fibonacci.md)
   * [File](File.md)
   * [FilterVar](FilterVar.md)
   * [Finite](Finite.md)

library/Exceptions/FibonacciException.php

@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Exceptions;
+
+class FibonacciException extends ValidationException
+{
+    public static $defaultTemplates = [
+        self::MODE_DEFAULT => [
+            self::STANDARD => '{{name}} must be a valid Fibonacci number',
+        ],
+        self::MODE_NEGATIVE => [
+            self::STANDARD => '{{name}} must not be a valid Fibonacci number',
+        ],
+    ];
+}

library/Rules/Fibonacci.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Rules;
+
+/**
+ * @author Samuel Heinzmann <samuel.heinzman@swisscom.com>
+ */
+class Fibonacci extends AbstractRule
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function validate($input)
+    {
+        if (!is_numeric($input)) {
+            return false;
+        }
+
+        $sequence = [0, 1];
+        $position = 1;
+        while ($input > $sequence[$position]) {
+            ++$position;
+            $sequence[$position] = $sequence[$position - 1] + $sequence[$position - 2];
+        }
+
+        return $sequence[$position] === (int) $input;
+    }
+}

library/Validator.php

@@ -63,6 +63,7 @@ use Respect\Validation\Rules\Key;
  * @method static Validator extension(string $extension)
  * @method static Validator factor(int $dividend)
  * @method static Validator falseVal()
+ * @method static Validator fibonacci()
  * @method static Validator file()
  * @method static Validator filterVar(int $filter, mixed $options = null)
  * @method static Validator finite()

tests/unit/Rules/FibonacciTest.php

@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * This file is part of Respect/Validation.
+ *
+ * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+namespace Respect\Validation\Rules;
+
+/**
+ * @group  rule
+ * @covers Respect\Validation\Rules\Fibonacci
+ */
+class FibonacciTest extends RuleTestCase
+{
+    public function providerForValidInput()
+    {
+        $rule = new Fibonacci();
+
+        return [
+            [$rule, 1],
+            [$rule, 2],
+            [$rule, 3],
+            [$rule, 5],
+            [$rule, 8.0],
+            [$rule, '3'],
+            [$rule, 21],
+            [$rule, 21.0],
+            [$rule, '21.0'],
+            [$rule, 34],
+            [$rule, '34'],
+            [$rule, 1346269],
+            [$rule, 10610209857723],
+        ];
+    }
+
+    public function providerForInvalidInput()
+    {
+        $rule = new Fibonacci();
+
+        return [
+            [$rule, 0],
+            [$rule, 1346268],
+            [$rule, ''],
+            [$rule, null],
+            [$rule, 7],
+            [$rule, -1],
+            [$rule, 5.2],
+            [$rule, '-1'],
+            [$rule, 'a'],
+            [$rule, ' '],
+            [$rule, false],
+            [$rule, true],
+        ];
+    }
+}