Test pulling pending tenants concurrently

tests/Etc/pull-worker.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Worker for the "concurrent pulls" tests.
+ * Separate OS process that boots the same test env and calls pullPendingFromPool().
+ * Since multiple processes run at once, they race for the pool.
+ *
+ * Used like `php pull-worker.php <startAtUnixFloat> <firstOrCreate:0|1>`
+ *
+ * Outputs the key of the pulled tenant, or "null" if nothing was pulled.
+ */
+
+require __DIR__ . '/../../vendor/autoload.php';
+
+use Stancl\Tenancy\Tests\Etc\Tenant;
+use Stancl\Tenancy\Tests\TestCase;
+
+$startAt = (float) ($argv[1] ?? 0);
+$firstOrCreate = ($argv[2] ?? '0') === '1';
+
+// createApplication() replays the suite's central-MySQL config without running setUp(),
+// so the pending tenants the parent test created survive into this process.
+(new class('pull-worker') extends TestCase {})->createApplication();
+
+// Wait so that every worker pulls at the same time
+if ($startAt > 0.0) {
+    time_sleep_until($startAt);
+}
+
+$tenant = Tenant::pullPendingFromPool($firstOrCreate);
+
+fwrite(STDOUT, $tenant?->getKey() ?? 'null');