Add a validator interface, UpperRangeValidator and OkValidator.

app/Models/Validation/Validators/OkValidator.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Models\Validation\Validators;
+
+use App\Models\Validation\Validators\ValidationInterface;
+
+class OkValidator implements ValidationInterface {
+    public function isValid(): bool
+    {
+        return true;
+    }
+}
+

app/Models/Validation/Validators/UpperRangeValidator.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Models\Validation\Validators;
+
+use App\Models\Validation\Validators\ValidationInterface;
+use App\Models\Validation\Validators\ValidationTrait;
+
+class UpperRangeValidator implements ValidationInterface {
+    private ValidationInterface $nextValidator;
+    private int $value;
+    private int $rangeLimit;
+
+    public function __construct(int $value, int $rangeLimit, ValidationInterface $nextValidator)
+    {
+        $this->value = $value;
+        $this->rangeLimit = $rangeLimit;
+        $this->nextValidator = $nextValidator;
+    }
+
+    public function isCurrentValid(): bool
+    {
+        if($this->value > $this->rangeLimit)
+            return false;
+
+        return true;
+    }
+
+    public function isValid(): bool
+    {
+        return $this->isCurrentValid() && $this->nextValidator->isValid();
+    }
+}
+

app/Models/Validation/Validators/ValidationInterface.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace App\Models\Validation\Validators;
+
+interface ValidationInterface {
+    public function isValid(): bool;
+}
+

tests/Unit/Validation/Validators/OkValidatorTest.php

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+<?php
+
+namespace Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+
+use App\Models\Validation\Validators\OkValidator;
+
+class OkValidatorTest extends TestCase
+{
+    public function testIsValid(): void
+    {
+        $validator = new OkValidator();
+
+        $this->assertTrue($validator->isValid());
+    }
+}

tests/Unit/Validation/Validators/UpperRangeValidatorTest.php

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+<?php
+
+namespace Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+
+use App\Models\Validation\Validators\UpperRangeValidator;
+use App\Models\Validation\Validators\OkValidator;
+
+class UpperRangeValidatorTest extends TestCase
+{
+    public function dataProvider() {
+        return [
+            'Valid Case for 10' => [
+                'value' => 10,
+                'limit' => 10,
+                'isValid' => true,
+            ],
+            'Valid Case for 255' => [
+                'value' => 0,
+                'limit' => 255,
+                'isValid' => true,
+            ],
+            'Invalid Case for 255' => [
+                'value' => 11,
+                'limit' => 10,
+                'isValid' => false,
+            ],
+            'Invalid Case for 255' => [
+                'value' => 256,
+                'limit' => 255,
+                'isValid' => false,
+            ],
+        ];
+    }
+
+    public function setUpValidator(int $value, int $rangeLimit): UpperRangeValidator
+    {
+        return new UpperRangeValidator($value, $rangeLimit, new OkValidator());
+    }
+
+    /**
+     * @dataProvider dataProvider
+     */
+    public function testGetMessage(int $value, int $limit, bool $isValid): void
+    {
+        $validator = $this->setUpValidator($value, $limit);
+
+        $this->assertEquals($validator->isValid(), $isValid);
+    }
+}