Add test environment initialization and conditional output handling adjustments

- Introduced `tests/bootstrap.php` for PHPUnit-specific setup.
- Updated `AbstractTransport` to check for test environment before modifying output settings.
- Adjusted `phpunit.xml.dist` to use the new bootstrap file.

Author: klapaudius

phpunit.xml.dist

@@ -3,7 +3,7 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.3/phpunit.xsd"
     backupGlobals="false"
-    bootstrap="vendor/autoload.php"
+    bootstrap="tests/bootstrap.php"
     colors="true"
     processIsolation="false"
     stopOnFailure="false"

src/Transports/AbstractTransport.php

@@ -148,7 +148,9 @@ protected function sendEvent(string $event, string $data): void
         echo sprintf('data: %s', $data).PHP_EOL;
         echo PHP_EOL;
 
-        if (false !== ob_get_length()) {
+        // Only flush when not in test environment
+        if (!defined('PHPUNIT_RUNNING')
+            && false !== ob_get_length()) {
             ob_flush();  // Flush PHP's output buffer first
         }
         flush();         // Then flush system/web server buffers

tests/bootstrap.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+// Define constant to indicate we're in a test environment
+define('PHPUNIT_RUNNING', true);
+
+// Load the composer autoloader
+require dirname(__DIR__).'/vendor/autoload.php';