feat: custom eventually assertion

tests/extensions/Async.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Appwrite\Tests;
+
+use PHPUnit\Framework\Assert;
+use Appwrite\Tests\Async\Eventually;
+
+trait Async
+{
+    public static function assertEventually(callable $probe, int $timeoutMilliseconds = 10000, int $waitMilliseconds = 500): void
+    {
+        Assert::assertThat($probe, new Eventually($timeoutMilliseconds, $waitMilliseconds));
+    }
+}

tests/extensions/Async/Eventually.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace Appwrite\Tests\Async;
+
+use PHPUnit\Framework\Constraint\Constraint;
+
+final class Eventually extends Constraint
+{
+    private int $timeoutMs;
+    private int $waitMs;
+
+    public function __construct(int $timeoutMs = 10000, int $waitMs = 500)
+    {
+        $this->timeoutMs = $timeoutMs;
+        $this->waitMs = $waitMs;
+    }
+
+    public function evaluate(mixed $probe, string $description = '', bool $returnResult = false): ?bool
+    {
+        if (!is_callable($probe)) {
+            throw new \Exception('Probe must be a callable');
+        }
+
+        $start = microtime(true);
+        $lastException = null;
+
+        do {
+            try {
+                $probe();
+                return true;
+            } catch (\Exception $exception) {
+                $lastException = $exception;
+            }
+
+            usleep($this->waitMs * 1000);
+        } while (microtime(true) - $start < $this->timeoutMs / 1000);
+
+        if ($returnResult) {
+            return false;
+        }
+
+        throw $lastException;
+    }
+
+    protected function failureDescription(mixed $other): string
+    {
+        return 'the given probe was satisfied within the provided timeout';
+    }
+
+    public function toString(): string
+    {
+        return 'Eventually';
+    }
+}