feat: add --memory usage flag

composer.json

@@ -79,6 +79,7 @@
         },
         "pest": {
             "plugins": [
+                "Pest\\Plugins\\Memory",
                 "Pest\\Plugins\\Coverage",
                 "Pest\\Plugins\\Init",
                 "Pest\\Plugins\\Version",

src/Plugins/Memory.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Plugins;
+
+use Pest\Contracts\Plugins\AddsOutput;
+use Pest\Contracts\Plugins\HandlesArguments;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * @internal
+ */
+final class Memory implements AddsOutput, HandlesArguments
+{
+    /** @var OutputInterface */
+    private $output;
+
+    private bool $enabled = false;
+
+    public function __construct(OutputInterface $output)
+    {
+        $this->output = $output;
+    }
+
+    public function handleArguments(array $arguments): array
+    {
+        foreach ($arguments as $index => $argument) {
+            if ($argument === '--memory') {
+                unset($arguments[$index]);
+
+                $this->enabled = true;
+            }
+        }
+
+        return array_values($arguments);
+    }
+
+    public function addOutput(int $result): int
+    {
+        if ($this->enabled) {
+            $this->output->writeln(sprintf(
+                '  <fg=white;options=bold>Memory: </><fg=default>%s MB</>',
+                round(memory_get_usage(true) / pow(1000, 2), 3)
+            ));
+        }
+
+        return $result;
+    }
+}