Add simple Firebird payload fake server to test suite

This is meant to test against certain fixed responses of Firebird
servers.  For now we add just a most basic test which verifies a
connection attempt.

Closes GH-6940.

ext/pdo_firebird/tests/payload_server.inc

@@ -0,0 +1,86 @@
+<?php
+
+function run_server(string $payloadFile): string {
+    $cmd = [getenv("TEST_PHP_EXECUTABLE"), "-n", __DIR__ . "/payload_server.php", $payloadFile];
+    $descriptorspec = array(
+        0 => STDIN,
+        1 => STDOUT,
+        2 => ['pipe', 'w'],
+    );
+    $proc = proc_open($cmd, $descriptorspec, $pipes);
+
+    // First, wait for the payload server to declare itself ready.
+    $bound = null;
+    stream_set_blocking($pipes[2], false);
+    for ($i = 0; $i < 60; $i++) {
+        usleep(50000); // 50ms per try
+        $status = proc_get_status($proc);
+        if (empty($status['running'])) {
+            echo "Server is not running\n";
+            proc_terminate($proc);
+            exit(1);
+        }
+        while (($line = fgets($pipes[2])) !== false) {
+            if (preg_match('/FB payload server listening on (.+)/', $line, $matches)) {
+                $bound = $matches[1];
+                // Now that we've identified the listen address, close STDERR.
+                // Otherwise the pipe may clog up with unread log messages.
+                fclose($pipes[2]);
+                break 2;
+            }
+        }
+    }
+
+    if ($bound === null) {
+        echo "Server did not output startup message";
+        proc_terminate($proc);
+        exit(1);
+    }
+
+    // Now wait for a connection to succeed.
+    // note: even when server prints 'FB payload server listening on localhost:12345'
+    //       it might not be listening yet...need to wait until fsockopen() call returns
+    $error = "Unable to connect to server\n";
+    for ($i=0; $i < 60; $i++) {
+        usleep(50000); // 50ms per try
+        $status = proc_get_status($proc);
+        $fp = fsockopen("tcp://$bound");
+        // Failure, the server is no longer running
+        if (!($status && $status['running'])) {
+            $error = "Server is not running\n";
+            break;
+        }
+        // Success, Connected to servers
+        if ($fp) {
+            $error = '';
+            break;
+        }
+    }
+
+    if ($fp) {
+        fclose($fp);
+    }
+
+    if ($error) {
+        echo $error;
+        proc_terminate($proc);
+        exit(1);
+    }
+
+    register_shutdown_function(
+        function($proc) {
+            proc_terminate($proc);
+            /* Wait for server to shutdown */
+            for ($i = 0; $i < 60; $i++) {
+                $status = proc_get_status($proc);
+                if (!($status && $status['running'])) {
+                    break;
+                }
+                usleep(50000);
+            }
+        },
+        $proc
+    );
+
+    return $bound;
+}

ext/pdo_firebird/tests/payload_server.php

@@ -0,0 +1,20 @@
+<?php
+
+$socket = stream_socket_server("tcp://localhost:0", $errno, $errstr);
+if (!$socket) {
+    echo "Can't start server: $errstr ($errno)\n";
+    exit(1);
+}
+
+$filename = $argv[1];
+$payload = file_get_contents($filename);
+if ($payload === false) {
+    echo "Can't read $filename\n";
+    exit(1);
+}
+
+fputs(STDERR, "FB payload server listening on " . stream_socket_get_name($socket, false) . "\n");
+
+while ($conn = stream_socket_accept($socket)) {
+    fwrite($conn, $payload);
+}

ext/pdo_firebird/tests/payload_test.phpt

@@ -0,0 +1,21 @@
+--TEST--
+FB payload server satisfies connection attempt
+--SKIPIF--
+<?php
+if (!extension_loaded('pdo_firebird')) die("skip pdo_firebird extension not available");
+if (!extension_loaded('sockets')) die("skip sockets extension not available");
+?>
+--FILE--
+<?php
+require_once "payload_server.inc";
+
+$address = run_server(__DIR__ . "/payload_test.data");
+
+// no need to change the credentials; we're running against a fake server
+$dsn = "firebird:dbname=inet://$address/test";
+$username = 'SYSDBA';
+$password = 'masterkey';
+
+new PDO($dsn, $username, $password, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
+?>
+--EXPECT--