Use aggregate with $out in executeReadWriteCommand tests

MongoDB 4.0.x (and possibly earlier) happens to require an $out stage for aggregate if a writeConcern option would be used. While this test doesn't use a write concern, it could inherit one from MONGODB_URI.

As for findAndModify, that is only considered a write command (does not accept a readConcern option).

Author: jmikola

tests/manager/manager-executeReadWriteCommand-001.phpt

@@ -4,20 +4,25 @@ MongoDB\Driver\Manager::executeReadWriteCommand()
 <?php require __DIR__ . "/../utils/basic-skipif.inc"; ?>
 <?php skip_if_not_live(); ?>
 <?php skip_if_not_clean(); ?>
-<?php skip_if_server_version('<', '3.2'); ?>
+<?php skip_if_server_version('<', '3.4'); /* aggregate write concern */ ?>
 --FILE--
 <?php
 require_once __DIR__ . "/../utils/basic.inc";
 require_once __DIR__ . "/../utils/observer.php";
 
 $manager = new MongoDB\Driver\Manager(URI);
 
+$command = new MongoDB\Driver\Command([
+    'aggregate' => COLLECTION_NAME,
+    'pipeline' => [
+        ['$group' => ['_id' => 1]],
+        ['$out' => COLLECTION_NAME . '.out'],
+    ],
+    'cursor' => (object) [],
+]);
+
 (new CommandObserver)->observe(
-    function() use ($manager) {
-        $command = new MongoDB\Driver\Command( [
-            'findAndModify' => NS,
-            'update' => [ '$set' => [ 'foo' => 'bar' ] ],
-        ] );
+    function() use ($manager, $command) {
         $manager->executeReadWriteCommand(
             DATABASE_NAME,
             $command,

tests/manager/manager-executeReadWriteCommand-002.phpt

@@ -26,7 +26,11 @@ var_dump($session->getServer() instanceof \MongoDB\Driver\Server);
 
 $command = new MongoDB\Driver\Command([
     'aggregate' => COLLECTION_NAME,
-    'pipeline' => [['$group' => ['_id' => 1]]],
+    'pipeline' => [
+        ['$group' => ['_id' => 1]],
+        /* Note: $out cannot be used in a transaction. This is technically not a
+         * write command, but it works for the purposes of this test. */
+    ],
     'cursor' => (object) []
 ]);
 $manager->executeReadWriteCommand(DATABASE_NAME, $command, ['session' => $session]);