tests: Add utility for running a HTTP server

Since the custom HTTP client in File based on curl cannot really be mocked,
let’s add an actual HTTP server to allow for integration and regression testing
during the transition to PSR-18 implementations.

tests/Integration/Fixtures/HttpServer.php

@@ -0,0 +1,158 @@
+<?php
+
+// SPDX-FileCopyrightText: 2004-2023 Ryan Parman, Sam Sneddon, Ryan McCue
+// SPDX-FileCopyrightText: 2023 Jan Tojnar
+// SPDX-License-Identifier: BSD-3-Clause
+
+declare(strict_types=1);
+
+namespace SimplePie\Tests\Integration\Fixtures;
+
+use Exception;
+
+final class HttpServer
+{
+    /**
+     * @var string
+     */
+    private $host = 'localhost';
+
+    /**
+     * @var int
+     */
+    private $port = 0;
+
+    /**
+     * @var string
+     */
+    private $routerPath;
+
+    /**
+     * @var resource|false
+     */
+    private $process = false;
+
+    /**
+     * @var resource|null
+     */
+    private $outputFd = null;
+
+    public function __construct(string $routerPath)
+    {
+        $this->routerPath = $routerPath;
+    }
+
+    public function start(): void
+    {
+        if ($this->process !== false) {
+            throw new Exception('Development server is already running.');
+        }
+
+        // PHP 8.0 supports auto-choosing port with `-S localhost:`
+        // but until we drop PHP 7 support, we need to choose a port ourselves.
+        $this->port = $this->findAvailablePort();
+
+        $command = $this->buildCommand();
+        // Capture stderr and stdout to custom file to avoid polluting the console output.
+        // If the pipes were connected to the default STDOUT/STDERR descriptors,
+        // even PHP’s output buffering would not able to capture the output of the child process.
+        $this->outputFd = fopen('php://temp', 'w+');
+        $descriptor_spec = [
+            1 => $this->outputFd,
+            2 => $this->outputFd,
+        ];
+        $this->process = proc_open($command, $descriptor_spec, $pipes);
+
+        if ($this->process === false) {
+            throw new Exception('Failed to start development server.');
+        }
+
+        $this->waitForServerToSettle();
+
+        register_shutdown_function(function (): void {
+            $this->terminate();
+        });
+    }
+
+    public function terminate(): void
+    {
+        if ($this->process === false) {
+            return;
+        }
+
+        fclose($this->outputFd);
+
+        proc_terminate($this->process);
+        proc_close($this->process);
+        $this->process = false;
+        $this->outputFd = null;
+    }
+
+    public function getBaseUri(): string
+    {
+        if ($this->process === false) {
+            throw new Exception('Development server is not running.');
+        }
+
+        return "http://{$this->host}:{$this->port}";
+    }
+
+    public function getConsoleOutput(): string
+    {
+        if ($this->process === false) {
+            throw new Exception('Development server is not running.');
+        }
+
+        rewind($this->outputFd);
+        $contents = stream_get_contents($this->outputFd);
+        return $contents === false ? '' : $contents;
+    }
+
+    private function findAvailablePort(): int
+    {
+        try {
+            $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
+
+            // Try to bind the socket to any open ephemeral port, see bind(2).
+            if (!socket_bind($socket, $this->host, 0)) {
+                throw new Exception('Could not bind to address');
+            }
+
+            socket_getsockname($socket, $checkAddress, $checkPort);
+        } finally {
+            socket_close($socket);
+        }
+
+        if ($checkPort > 0) {
+            return $checkPort;
+        }
+
+        throw new Exception('Failed to find an open port.');
+    }
+
+    private function buildCommand(): string
+    {
+        return implode(' ', [
+            'php',
+            '-S',
+            escapeshellarg("{$this->host}:{$this->port}"),
+            escapeshellarg($this->routerPath),
+        ]);
+    }
+
+    private function waitForServerToSettle(): void
+    {
+        // Wait up to 5 seconds.
+        for ($i = 0; $i <= 50; $i++) {
+            usleep(100000); // 100 ms
+
+            $socket = @fsockopen($this->host, $this->port);
+            if ($socket !== false) {
+                fclose($socket);
+                return;
+            }
+        }
+
+        throw new Exception('Unable to connect to development server.');
+    }
+}