diff --git a/README.md b/README.md
index cb4c01e..719cb88 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,7 @@ class ArticlePage extends \Kirby\Cms\Page
 {
     use \Bnomei\ModelWithNitro;
 }
-``
+```
 
 > [!NOTE]
 > You can also use the trait for user models. File models are patched automatically.
diff --git a/classes/Nitro.php b/classes/Nitro.php
index 74d94ad..1ccd085 100644
--- a/classes/Nitro.php
+++ b/classes/Nitro.php
@@ -4,7 +4,10 @@
 
 use Bnomei\Nitro\DirInventory;
 use Bnomei\Nitro\SingleFileCache;
+use Closure;
+use Kirby\Cache\FileCache;
 use Kirby\Cms\App;
+use Kirby\Cms\Files;
 use Kirby\Filesystem\Dir;
 use Kirby\Filesystem\F;
 use Kirby\Toolkit\Str;
@@ -18,17 +21,20 @@ class Nitro
 
     private ?SingleFileCache $singleFileCache = null;
 
+    /**
+     * @var true
+     */
+    private bool $_ready = false;
+
     public function __construct(array $options = [])
     {
         $this->options = array_merge([
-            'enabled' => true,
             'cacheDir' => realpath(__DIR__.'/../').'/cache',
-            'cacheType' => 'json',
             'json-encode-flags' => JSON_THROW_ON_ERROR,
         ], $options);
 
         foreach ($this->options as $key => $value) {
-            if ($value instanceof \Closure) {
+            if ($value instanceof Closure) {
                 $this->options[$key] = $value();
             }
         }
@@ -66,6 +72,13 @@ public function ready(): void
         $this->replaceCacheFolderWithSymlink();
         $this->patchFilesClass();
         $this->dir()->patchDirClass();
+
+        $this->_ready = true;
+    }
+
+    public function isReady(): bool
+    {
+        return $this->_ready;
     }
 
     /*
@@ -73,12 +86,8 @@ public function ready(): void
      */
     private function replaceCacheFolderWithSymlink(): bool
     {
-        if (! $this->options['enabled']) {
-            return false;
-        }
-
         $internalDir = $this->options['cacheDir'];
-        /** @var \Kirby\Cache\FileCache $cache */
+        /** @var FileCache $cache */
         $cache = kirby()->cache('bnomei.nitro.dir');
         $kirbyDir = $cache->root();
 
@@ -97,18 +106,18 @@ private function replaceCacheFolderWithSymlink(): bool
         return true;
     }
 
-    private function patchFilesClass(): void
+    public function patchFilesClass(): bool
     {
         if (option('bnomei.nitro.patch-files-class') !== true) {
-            return;
+            return false;
         }
 
         $patch = $this->options['cacheDir'].'/files.'.App::versionHash().'.patch';
         if (file_exists($patch)) {
-            return;
+            return false;
         }
 
-        $filesClass = (new ReflectionClass(\Kirby\Cms\Files::class))->getFileName();
+        $filesClass = (new ReflectionClass(Files::class))->getFileName();
         if ($filesClass && F::exists($filesClass) && F::isWritable($filesClass)) {
             $code = F::read($filesClass);
             if ($code && Str::contains($code, '\Bnomei\NitroFile::factory') === false) {
@@ -116,11 +125,14 @@ private function patchFilesClass(): void
                 F::write($filesClass, $code);
 
                 if (function_exists('opcache_invalidate')) {
-                    opcache_invalidate($filesClass);
+                    opcache_invalidate($filesClass); // @codeCoverageIgnore
                 }
             }
-            F::write($patch, date('c'));
+
+            return F::write($patch, date('c'));
         }
+
+        return false;
     }
 
     public function modelIndex(): int
diff --git a/classes/Nitro/AbortCachingExeption.php b/classes/Nitro/AbortCachingExeption.php
index b64c763..caa3250 100644
--- a/classes/Nitro/AbortCachingExeption.php
+++ b/classes/Nitro/AbortCachingExeption.php
@@ -4,7 +4,7 @@
 
 class AbortCachingExeption extends \Exception
 {
-    public function __construct($message = 'Abort Caching', $code = 0, ?\Throwable $previous = null)
+    public function __construct(string $message = 'Abort Caching', int $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
     }
diff --git a/classes/Nitro/DirInventory.php b/classes/Nitro/DirInventory.php
index 1ba81e2..971dead 100644
--- a/classes/Nitro/DirInventory.php
+++ b/classes/Nitro/DirInventory.php
@@ -14,7 +14,7 @@ class DirInventory
 
     private bool $isDirty;
 
-    private array $options = [];
+    private array $options;
 
     public function __construct(array $options = [])
     {
@@ -28,54 +28,29 @@ public function __construct(array $options = [])
 
     public function __destruct()
     {
-        if (! $this->isDirty || ! $this->enabled()) {
-            return;
-        }
-
-        $file = $this->file();
-
-        if ($this->cacheType() === 'php') {
-            F::write($file, '<?php'.PHP_EOL.' return '.var_export($this->data, true).';');
-            if (function_exists('opcache_invalidate')) {
-                opcache_invalidate($file);
-            }
-        } else {
-            F::write($file, json_encode($this->data, $this->options['json-encode-flags']));
-        }
+        $this->write();
     }
 
     public function file(): string
     {
-        if ($this->cacheType() === 'php') {
-            return $this->cacheDir().'/dir-inventory.php';
-        }
-
         return $this->cacheDir().'/dir-inventory.json';
     }
 
     private function load(): void
     {
-        if (! $this->enabled() || ! file_exists($this->file())) {
+        if (! file_exists($this->file())) {
             return;
         }
 
-        if ($this->cacheType() === 'php') {
-            $this->data = include $this->file();
-        } else {
-            $data = file_get_contents($this->file());
-            $data = $data ? json_decode($data, true) : [];
-            if (is_array($data) || is_null($data)) {
-                $this->data = $data;
-            }
+        $data = file_get_contents($this->file());
+        $data = $data ? json_decode($data, true) : [];
+        if (is_array($data) || is_null($data)) {
+            $this->data = $data;
         }
     }
 
     public function get(string|array $key): ?array
     {
-        if (! $this->enabled()) {
-            return null;
-        }
-
         $key = $this->key($key);
 
         return A::get($this->data, $key);
@@ -83,10 +58,6 @@ public function get(string|array $key): ?array
 
     public function set(string|array $key, ?array $input = null): void
     {
-        if (! $this->enabled()) {
-            return;
-        }
-
         $this->isDirty = true;
         $key = $this->key($key);
         $this->data[$key] = $input;
@@ -108,31 +79,16 @@ private function key(string|array $key): string
         return is_array($key) ? hash('xxh3', print_r($key, true)) : $key;
     }
 
-    private function enabled(): bool
-    {
-        return $this->options['enabled'];
-    }
-
-    private function cacheDir(): string
+    public function cacheDir(): string
     {
         return $this->options['cacheDir'];
     }
 
-    private function cacheType(): string
+    public function patchDirClass(): bool
     {
-        return $this->options['cacheType'];
-    }
-
-    public function patchDirClass(): void
-    {
-
-        if (! $this->enabled()) {
-            return;
-        }
-
         $patch = $this->cacheDir().'/dir-inventory.'.App::versionHash().'.patch';
         if (file_exists($patch)) {
-            return;
+            return false;
         }
 
         $reflection = new ReflectionClass(Dir::class);
@@ -141,7 +97,7 @@ public function patchDirClass(): void
         $content = $file ? file_get_contents($file) : null;
 
         if (! $file || ! $content) {
-            return;
+            return false;
         }
 
         $head = <<<'CODE'
@@ -171,10 +127,22 @@ public function patchDirClass(): void
             F::write($file, $content);
 
             if (function_exists('opcache_invalidate')) {
-                opcache_invalidate($file);
+                opcache_invalidate($file); // @codeCoverageIgnore
             }
         }
 
-        F::write($patch, date('c'));
+        return F::write($patch, date('c'));
+    }
+
+    public function write(): bool
+    {
+        if (! $this->isDirty) {
+            return false;
+        }
+
+        $file = $this->file();
+        $this->isDirty = false;
+
+        return F::write($file, json_encode($this->data, $this->options['json-encode-flags']));
     }
 }
diff --git a/classes/Nitro/SingleFileCache.php b/classes/Nitro/SingleFileCache.php
index 766faff..882e3d4 100644
--- a/classes/Nitro/SingleFileCache.php
+++ b/classes/Nitro/SingleFileCache.php
@@ -80,7 +80,7 @@ public function set(string|array $key, mixed $value, int $minutes = 0): bool
 
         $this->data[$key] = (new Value($value, $minutes))->toArray();
         $this->isDirty++;
-        if ($this->isDirty > $this->options['max-dirty-cache']) {
+        if ($this->isDirty >= $this->options['max-dirty-cache']) {
             $this->write();
         }
 
@@ -90,7 +90,7 @@ public function set(string|array $key, mixed $value, int $minutes = 0): bool
     /**
      * {@inheritDoc}
      */
-    public function retrieve(string|array $key): ?Value
+    public function retrieve(string $key): ?Value
     {
         $value = A::get($this->data, $this->key($key));
 
@@ -101,12 +101,16 @@ public function retrieve(string|array $key): ?Value
         return is_array($value) ? Value::fromArray($value) : $value;
     }
 
-    public function get(string $key, mixed $default = null): mixed
+    public function get(array|string $key, mixed $default = null): mixed
     {
         if ($this->options['debug']) {
             return $default;
         }
 
+        if (is_array($key)) {
+            $key = print_r($key, true);
+        }
+
         return parent::get($key, $default);
     }
 
@@ -119,7 +123,7 @@ public function remove(string|array $key): bool
         if (array_key_exists($key, $this->data)) {
             unset($this->data[$key]);
             $this->isDirty++;
-            if ($this->isDirty > $this->options['max-dirty-cache']) {
+            if ($this->isDirty >= $this->options['max-dirty-cache']) {
                 $this->write();
             }
         }
@@ -161,10 +165,9 @@ public function write(): bool
         if ($this->isDirty === 0) {
             return false;
         }
-        F::write($this->file(), json_encode($this->data, $this->options['json-encode-flags']));
         $this->isDirty = 0;
 
-        return true;
+        return F::write($this->file(), json_encode($this->data, $this->options['json-encode-flags']));
     }
 
     private static function isCallable(mixed $value): bool
@@ -195,4 +198,9 @@ public function serialize(mixed $value): mixed
 
         return $value;
     }
+
+    public function count(): int
+    {
+        return count($this->data);
+    }
 }
diff --git a/index.php b/index.php
index b183b47..9952133 100644
--- a/index.php
+++ b/index.php
@@ -43,9 +43,6 @@ function nitro(): \Bnomei\Nitro
             'args' => [],
             'command' => static function ($cli): void {
 
-                $kirby = $cli->kirby();
-                $kirby->impersonate('kirby');
-
                 $cli->out('Indexing...');
                 $count = nitro()->modelIndex();
                 $cli->out($count.' models indexed.');
diff --git a/tests/NitroTest.php b/tests/NitroTest.php
index faaead4..f3f5e7b 100644
--- a/tests/NitroTest.php
+++ b/tests/NitroTest.php
@@ -1,6 +1,8 @@
 <?php
 
 use Bnomei\Nitro;
+use Kirby\Filesystem\Dir;
+use Kirby\Filesystem\F;
 
 beforeEach(function () {
     nitro()->flush(); // cleanup
@@ -13,11 +15,27 @@
 });
 
 it('can use the cache', function () {
+    Nitro::$singleton = null;
+
+    // force instant writes for this test
+    Nitro::singleton([
+        'max-dirty-cache' => 1,
+    ]);
+
     $cache = nitro()->cache();
     $cache->set('test', 'value');
     $value = $cache->get('test');
 
     expect($value)->toBe('value');
+
+    $cache->set(['test'], 'value');
+    $value = $cache->get(['test']);
+
+    expect($value)->toBe('value');
+
+    $cache->remove('test');
+
+    expect($cache->get('test'))->toBeNull();
 });
 
 it('will serialize kirby\content\fields to their value', function () {
@@ -64,3 +82,151 @@
 
     expect($cache->get('test'))->toBe('value');
 });
+
+it('can have a closure as option', function () {
+    Nitro::$singleton = null;
+    Nitro::singleton(['test' => function () {
+        return 'value';
+    }]);
+
+    expect(nitro()->option('test'))->toBe('value');
+});
+
+it('will create the local cache dir if it is missing', function () {
+    Nitro::$singleton = null;
+
+    expect(Dir::remove(__DIR__.'/../cache'))->toBeTrue();
+    expect(Dir::exists(__DIR__.'/../cache'))->toBeFalse();
+
+    nitro();
+
+    expect(Dir::exists(nitro()->option('cacheDir')))->toBeTrue();
+});
+
+it('has a ready method to apply the monkey patches', function () {
+    Nitro::$singleton = null;
+    nitro()->ready();
+
+    expect(nitro()->isReady())->toBeTrue();
+});
+
+it('will remove files and folder when flushing but not break symlinks', function () {
+    $dir = __DIR__.'/../cache';
+    $inode = fileinode($dir);
+    F::write($dir.'/test.txt', 'test');
+    Dir::make($dir.'/test');
+
+    nitro()->flush();
+
+    expect(F::exists($dir.'/test.txt'))->toBeFalse()
+        ->and(Dir::exists($dir.'/test'))->toBeFalse()
+        ->and(fileinode($dir))->toBe($inode);
+});
+
+it('can update its index', function () {
+    $count = nitro()->modelIndex();
+
+    expect($count)->toBeGreaterThan(0);
+});
+
+it('will symlink the kirby cache folder to the local cache folder so the dir index is the same', function () {
+
+    Nitro::$singleton = null;
+
+    $internalDir = nitro()->option('cacheDir');
+    $cache = kirby()->cache('bnomei.nitro.dir');
+    $kirbyDir = $cache->root();
+
+    Dir::remove($internalDir); // should be created if missing
+    @unlink($kirbyDir); // is file but should be symlink
+    Dir::make($kirbyDir); // is dir but should be symlink
+
+    nitro()->ready();
+
+    expect(is_link($kirbyDir))->toBeTrue()
+        ->and(readlink($kirbyDir))->toBe($internalDir);
+});
+
+it('can patch the files class', function () {
+    Nitro::$singleton = null;
+
+    $patch = nitro()->option('cacheDir').'/files.'.kirby()->versionHash().'.patch';
+    F::remove($patch);
+
+    $success = nitro()->patchFilesClass();
+
+    expect(F::exists($patch))->toBeTrue()
+        ->and($success)->toBeTrue()
+        ->and(nitro()->patchFilesClass())->toBeFalse();
+});
+
+it('can patch the dir class', function () {
+    Nitro::$singleton = null;
+
+    $patch = nitro()->option('cacheDir').'/dir-inventory.'.kirby()->versionHash().'.patch';
+    F::remove($patch);
+
+    $success = nitro()->dir()->patchDirClass();
+
+    expect(F::exists($patch))->toBeTrue()
+        ->and($success)->toBeTrue()
+        ->and(nitro()->dir()->patchDirClass())->toBeFalse();
+});
+
+it('can flush the dir cache', function () {
+    nitro()->modelIndex();
+    $di = nitro()->dir();
+    $di->write(); // force now, not on destruct
+
+    expect(Dir::files($di->cacheDir()))->toHaveCount(1)
+        ->and($di->write())->toBeFalse();
+
+    $di->flush();
+
+    expect(Dir::files($di->cacheDir()))->toHaveCount(0);
+});
+
+it('can serialize even null values', function () {
+    $cache = nitro()->cache();
+    $cache->set('null', null);
+
+    $value = $cache->get('null');
+
+    expect($value)->toBeNull()
+        ->and($cache->count())->toBe(1);
+});
+
+it('will update the model cache if the model is updated', function () {
+    nitro()->modelIndex();
+    $cache = nitro()->cache();
+
+    $home = page('home');
+    kirby()->impersonate('kirby');
+    $home = $home->update([
+        'title' => 'new title',
+    ]);
+
+    $value = $cache->get($home->keyNitro());
+    expect($value)->toHaveKey('title', 'new title');
+
+    // reset
+    $home->update([
+        'title' => 'Home',
+    ]);
+});
+
+it('will update the model cache if the model is deleted', function () {
+    $home = page('home');
+    kirby()->impersonate('kirby');
+    $page = $home->createChild([
+        'slug' => 'test',
+    ]);
+
+    nitro()->modelIndex();
+    $cache = nitro()->cache();
+    $count = $cache->count();
+
+    $page->delete(true);
+
+    expect($cache->count())->toBe($count - 1);
+});
diff --git a/tests/content/home/home.en.txt b/tests/content/home/home.en.txt
index f0c69ed..e8c56e3 100644
--- a/tests/content/home/home.en.txt
+++ b/tests/content/home/home.en.txt
@@ -2,4 +2,12 @@ Title: Home
 
 ----
 
+Text: 
+
+----
+
+Nt-text: 
+
+----
+
 Uuid: EKIXBbdWvX54TqqQ
\ No newline at end of file