feat: adds snapshot testing

src/Plugins/Snapshot.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Plugins;
+
+use Pest\Contracts\Plugins\HandlesArguments;
+use Pest\TestSuite;
+
+/**
+ * @internal
+ */
+final class Snapshot implements HandlesArguments
+{
+    use Concerns\HandleArguments;
+
+    /**
+     * {@inheritDoc}
+     */
+    public function handleArguments(array $arguments): array
+    {
+        if (! $this->hasArgument('--update-snapshots', $arguments)) {
+            return $arguments;
+        }
+
+        TestSuite::getInstance()->snapshots->flush();
+
+        return $this->popArgument('--update-snapshots', $arguments);
+    }
+}