test: add infrastructure for mocking native header functions

Author: datamweb

tests/_support/Debug/MockNativeHeaders.php

@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Debug;
+
+/**
+ * Class MockNativeHeaders
+ *
+ * This class serves as a container to hold the state of HTTP headers
+ * during unit testing. It allows the framework to simulate sending headers
+ * without actually outputting them to the CLI or browser.
+ */
+class MockNativeHeaders
+{
+    /**
+     * Simulates the state of whether headers have been sent.
+     */
+    public static bool $headersSent = false;
+
+    /**
+     * Stores the list of headers that have been sent.
+     */
+    public static array $headers = [];
+
+    /**
+     * Resets the class state to defaults.
+     * Useful for cleaning up between individual tests.
+     */
+    public static function reset(): void
+    {
+        self::$headersSent = false;
+        self::$headers     = [];
+    }
+}
+
+/**
+ * Mock implementation of the native PHP headers_sent() function.
+ *
+ * Instead of checking the actual PHP output buffer, this function
+ * checks the static property in MockNativeHeaders.
+ *
+ * @return bool True if headers are considered sent, false otherwise.
+ */
+function headers_sent(): bool
+{
+    return MockNativeHeaders::$headersSent;
+}
+
+/**
+ * Mock implementation of the native PHP headers_list() function.
+ *
+ * Retrieves the array of headers stored in the MockNativeHeaders class
+ * rather than the actual headers sent by the server.
+ *
+ * @return array The list of simulated headers.
+ */
+function headers_list(): array
+{
+    return MockNativeHeaders::$headers;
+}