Add sendAudio method to Bot

tests/TgBotLib/Methods/SendAudioTest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace TgBotLib\Methods;
+
+use PHPUnit\Framework\TestCase;
+use TgBotLib\Bot;
+use TgBotLib\Enums\Types\ParseMode;
+use TgBotLib\Objects\LinkPreviewOptions;
+use TgBotLib\Objects\Message;
+
+class SendAudioTest extends TestCase
+{
+    const string TEST_AUDIO_PATH = __DIR__ . DIRECTORY_SEPARATOR . 'sample' . DIRECTORY_SEPARATOR . 'ketchup.mp3';
+    private static Bot $bot;
+
+    /**
+     * @return void
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$bot = new Bot(BOT_TOKEN);
+    }
+
+    /**
+     * Tests the `sendMessage` function of the bot instance.
+     *
+     * @return void
+     */
+    public function testSendAudio(): void
+    {
+        $result = self::$bot->sendAudio(
+            chat_id: TEST_CHAT_ID,
+            audio: self::TEST_AUDIO_PATH,
+            caption: 'Test Unit: testSendAudio',
+        );
+
+        $this->assertInstanceOf(Message::class, $result);
+        $this->assertEquals('Test Unit: testSendAudio', $result->getCaption());
+    }
+
+}