Add test for renderer custom language array

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: jfcherng

tests/Renderer/RendererTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Jfcherng\Diff\Test\Renderer;
+
+use Jfcherng\Diff\DiffHelper;
+use Jfcherng\Diff\Renderer\AbstractRenderer;
+use Jfcherng\Diff\Utility\Language;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test general methods from the AbstractRenderer.
+ *
+ * @coversNothing
+ *
+ * @internal
+ */
+final class RendererTest extends TestCase
+{
+    /**
+     * Test the AbstractRenderer::setOptions with custom language array.
+     *
+     * @covers \Jfcherng\Diff\Renderer\AbstractRenderer::setOptions
+     */
+    public function testSetOptionsWithCustomLanguageArray(): void
+    {
+        $languageArrayDefault = (new Language('eng'))->getTranslations();
+        $languageArrayTest = ['differences' => '_TEST_MARKER_'] + $languageArrayDefault;
+
+        $diffResult = DiffHelper::calculate(
+            'foo',
+            'bar',
+            'Inline',
+            [],
+            ['language' => $languageArrayTest]
+        );
+
+        static::assertStringContainsString(
+            '_TEST_MARKER_',
+            $diffResult,
+            'Rederer options: custom "language" array should work.'
+        );
+    }
+}