Add tests for the -threshold option.

Author: Pierstoval

Tests/References/ThresholdTest.php

@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the OrbitaleImageMagickPHP package.
+ *
+ * (c) Alexandre Rock Ancelet <alex@orbitale.io>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Orbitale\Component\ImageMagick\Tests\References;
+
+use Orbitale\Component\ImageMagick\References;
+use PHPUnit\Framework\TestCase;
+
+class ThresholdTest extends TestCase
+{
+    /**
+     * @var References
+     */
+    private $ref;
+
+    public function __construct($name = null, array $data = [], $dataName = '')
+    {
+        parent::__construct($name, $data, $dataName);
+        $this->ref = new References();
+    }
+
+    /**
+     * @dataProvider provideValidThresholdValues
+     */
+    public function testValidThreshold(string $value): void
+    {
+        $threshold = $this->ref->threshold($value);
+
+        self::assertSame($threshold, $value);
+    }
+
+    public function provideValidThresholdValues(): \Generator
+    {
+        yield '100' => ['100'];
+        yield '-100' => ['-100'];
+        yield '0' => ['0'];
+        yield '100%' => ['100%'];
+        yield '-100%' => ['-100%'];
+        yield '0%' => ['0%'];
+    }
+
+    /**
+     * @dataProvider provideInvalidThresholdValues
+     */
+    public function testInvalidThreshold(string $value): void
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage(\sprintf(
+            'The specified threshold parameter (%s) is invalid.'."\n".'The value must be an integer or a percentage value'."\n".'Please refer to ImageMagick command line documentation:'."\n%s",
+            $value,
+            'http://www.imagemagick.org/script/command-line-options.php#threshold'
+        ));
+
+        $this->ref->threshold($value);
+    }
+
+    public function provideInvalidThresholdValues(): \Generator
+    {
+        yield 'Empty string' => [''];
+        yield 'a' => ['a'];
+        yield '-' => ['-'];
+        yield '.' => ['.'];
+        yield '1_00' => ['1_00'];
+        yield '%' => ['%'];
+        yield 'a%' => ['a%'];
+        yield '-%' => ['-%'];
+        yield '.%' => ['.%'];
+        yield '1_00%' => ['1_00%'];
+    }
+}