diff --git a/.gitignore b/.gitignore
index 06024100..6f7ff152 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,4 +7,3 @@ plugins/*
 storage/textures/*
 storage/update_cache/*
 node_modules/*
-resources/assets/src/bower_components/*
diff --git a/app/Http/Controllers/UpdateController.php b/app/Http/Controllers/UpdateController.php
index 39595e60..e9de1066 100644
--- a/app/Http/Controllers/UpdateController.php
+++ b/app/Http/Controllers/UpdateController.php
@@ -7,6 +7,7 @@ use Log;
 use Utils;
 use File;
 use Option;
+use Storage;
 use ZipArchive;
 use App\Services\OptionForm;
 use Illuminate\Http\Request;
@@ -114,8 +115,8 @@ class UpdateController extends Controller
                 $update_cache = storage_path('update_cache');
 
                 if (!is_dir($update_cache)) {
-                    if (false === mkdir($update_cache)) {
-                        exit(trans('admin.update.errors.write-permission'));
+                    if (false === Storage::disk('storage')->makeDirectory('update_cache')) {
+                        return response(trans('admin.update.errors.write-permission'));
                     }
                 }
 
@@ -125,8 +126,6 @@ class UpdateController extends Controller
 
                 return json(compact('release_url', 'tmp_path', 'file_size'));
 
-                break;
-
             case 'start-download':
 
                 if (!session()->has('tmp_path')) return "No temp path is set.";
@@ -137,13 +136,11 @@ class UpdateController extends Controller
                 } catch (\Exception $e) {
                     File::delete($tmp_path);
 
-                    exit(trans('admin.update.errors.prefix').$e->getMessage());
+                    return response(trans('admin.update.errors.prefix').$e->getMessage());
                 }
 
                 return json(compact('tmp_path'));
 
-                break;
-
             case 'get-file-size':
 
                 if (!session()->has('tmp_path')) return "No temp path is set.";
@@ -152,11 +149,10 @@ class UpdateController extends Controller
                     return json(['size' => filesize($tmp_path)]);
                 }
 
-                break;
-
             case 'extract':
 
-                if (!file_exists($tmp_path)) exit('No file available');
+                if (!file_exists($tmp_path))
+                    return response('No file available');
 
                 $extract_dir = storage_path("update_cache/{$this->latestVersion}");
 
@@ -166,14 +162,12 @@ class UpdateController extends Controller
                 if ($res === true) {
                     Log::info("[ZipArchive] Extracting file $tmp_path");
 
-                    try {
-                        $zip->extractTo($extract_dir);
-                    } catch (\Exception $e) {
-                        exit(trans('admin.update.errors.prefix').$e->getMessage());
+                    if ($zip->extractTo($extract_dir) === false) {
+                        return response(trans('admin.update.errors.prefix').'Cannot unzip file.');
                     }
 
                 } else {
-                    exit(trans('admin.update.errors.unzip').$res);
+                    return response(trans('admin.update.errors.unzip').$res);
                 }
                 $zip->close();
 
@@ -190,24 +184,22 @@ class UpdateController extends Controller
                     File::copyDirectory($extract_dir, base_path());
 
                     Log::info("[Extracter] Covering files");
-                    File::deleteDirectory(storage_path('update_cache'));
-
-                    Log::info("[Extracter] Cleaning cache");
 
                 } catch (\Exception $e) {
                     Log::error("[Extracter] Error occured when covering files", [$e]);
 
+                    // Response can be returned, while cache will be cleared
+                    // @see https://gist.github.com/g-plane/2f88ad582826a78e0a26c33f4319c1e0
+                    return response(trans('admin.update.errors.overwrite').$e->getMessage());
+                } finally {
                     File::deleteDirectory(storage_path('update_cache'));
-                    exit(trans('admin.update.errors.overwrite').$e->getMessage());
+                    Log::info("[Extracter] Cleaning cache");
                 }
 
                 return json(trans('admin.update.complete'), 0);
 
-                break;
-
             default:
-                # code...
-                break;
+                return json(trans('general.illegal-parameters'), 1);
         }
     }
 
@@ -215,7 +207,9 @@ class UpdateController extends Controller
     {
         if (!$this->updateInfo) {
             // add timestamp to control cdn cache
-            $url = $this->updateSource."?v=".substr(time(), 0, -3);
+            $url = starts_with($this->updateSource, 'http')
+                ? $this->updateSource."?v=".substr(time(), 0, -3)
+                : $this->updateSource;
 
             try {
                 $response = file_get_contents($url);
diff --git a/tests/UpdateControllerTest.php b/tests/UpdateControllerTest.php
new file mode 100644
index 00000000..c615e1c2
--- /dev/null
+++ b/tests/UpdateControllerTest.php
@@ -0,0 +1,212 @@
+<?php
+
+use Illuminate\Support\Facades\File;
+use Illuminate\Foundation\Testing\WithoutMiddleware;
+use Illuminate\Foundation\Testing\DatabaseMigrations;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+
+class UpdateControllerTest extends TestCase
+{
+    use DatabaseTransactions;
+
+    protected function setUp()
+    {
+        parent::setUp();
+        return $this->actAs('admin');
+    }
+
+    /**
+     * @param  string $version
+     * @param  bool   $is_pre_release
+     * @return string
+     */
+    protected function generateFakeUpdateInfo($version, $is_pre_release = false) {
+        $time = \Carbon\Carbon::now();
+        file_put_contents(storage_path('testing/update.json'), json_encode([
+            'app_name' => 'blessing-skin-server',
+            'latest_version' => $version,
+            'update_time' => $time->getTimestamp(),
+            'releases' => [
+                $version => [
+                    'version' => $version,
+                    'pre_release' => $is_pre_release,
+                    'release_time' => $time->getTimestamp(),
+                    'release_note' => 'test',
+                    'release_url' => storage_path('testing/update.zip')
+                ]
+            ]
+        ]));
+
+        return $time->toDateTimeString();
+    }
+
+    protected function generateFakeUpdateFile()
+    {
+        if (file_exists(storage_path('testing/update.zip'))) {
+            unlink(storage_path('testing/update.zip'));
+        }
+
+        $zip = new ZipArchive();
+        $zip->open(storage_path('testing/update.zip'), ZipArchive::CREATE);
+        $zip->addEmptyDir('coverage');
+        $zip->close();
+    }
+
+    public function testShowUpdatePage()
+    {
+        option(['update_source' => 'http://xxx.xx/']);
+        $this->visit('/admin/update')
+            ->see(trans('admin.update.errors.connection'))
+            ->see(config('app.version'))
+            ->uncheck('check_update')
+            ->type(storage_path('testing/update.json'), 'update_source')
+            ->press('submit_update');
+        $this->assertFalse(option('check_update'));
+        $this->assertEquals(
+            storage_path('testing/update.json'),
+            option('update_source')
+        );
+
+        $time = $this->generateFakeUpdateInfo('4.0.0');
+        $this->visit('/admin/update')
+            ->see(config('app.version'))
+            ->see('4.0.0')
+            ->see('test')
+            ->see($time);
+
+        file_put_contents(storage_path('testing/update.json'), json_encode([
+            'latest_version' => '4.0.0'
+        ]));
+        $this->visit('/admin/update')
+            ->see(trans('admin.update.info.pre-release'));
+    }
+
+    public function testCheckUpdates()
+    {
+        option(['update_source' => 'http://xxx.xx/']);
+
+        // Source is unavailable
+        $this->get('/admin/update/check')
+            ->seeJson([
+                'latest' => null,
+                'available' => false
+            ]);
+
+        option(['update_source' => storage_path('testing/update.json')]);
+        $this->generateFakeUpdateInfo('4.0.0');
+        $this->get('/admin/update/check')
+            ->seeJson([
+                'latest' => '4.0.0',
+                'available' => true
+            ]);
+    }
+
+    public function testDownload()
+    {
+        option(['update_source' => storage_path('testing/update.json')]);
+        $this->generateFakeUpdateInfo('0.1.0');
+        $this->get('/admin/update/download');
+
+        $this->generateFakeUpdateFile();
+
+        // Prepare for downloading
+        Storage::disk('storage')->deleteDirectory('update_cache');
+        $this->generateFakeUpdateInfo('4.0.0');
+        Storage::shouldReceive('disk')
+            ->with('storage')
+            ->once()
+            ->andReturnSelf();
+        Storage::shouldReceive('makeDirectory')
+            ->with('update_cache')
+            ->once()
+            ->andReturn(false);
+        $this->get('/admin/update/download?action=prepare-download')
+            ->see(trans('admin.update.errors.write-permission'));
+
+        mkdir(storage_path('update_cache'));
+        $this->get('/admin/update/download?action=prepare-download')
+            ->seeJson([
+                'release_url' => storage_path('testing/update.zip'),
+                'file_size' => filesize(storage_path('testing/update.zip'))
+            ])
+            ->assertSessionHas('tmp_path');
+
+        // Start downloading
+        $this->flushSession();
+        $this->actAs('admin')
+            ->get('/admin/update/download?action=start-download')
+            ->see('No temp path is set.');
+
+        unlink(storage_path('testing/update.zip'));
+        $this->withSession(['tmp_path' => storage_path('update_cache/update.zip')])
+            ->get('/admin/update/download?action=start-download')
+            ->see(trans('admin.update.errors.prefix'));
+
+        $this->generateFakeUpdateFile();
+        $this->get('/admin/update/download?action=start-download')
+            ->seeJson([
+                'tmp_path' => storage_path('update_cache/update.zip')
+            ]);
+        $this->assertFileExists(storage_path('update_cache/update.zip'));
+
+        // Get file size
+        $this->flushSession();
+        $this->actAs('admin')
+            ->get('/admin/update/download?action=get-file-size')
+            ->see('No temp path is set.');
+
+        $this->withSession(['tmp_path' => storage_path('update_cache/update.zip')])
+            ->get('/admin/update/download?action=get-file-size')
+            ->seeJson([
+                'size' => filesize(storage_path('testing/update.zip'))
+            ]);
+
+        // Extract
+        $this->withSession(['tmp_path' => storage_path('update_cache/update')])
+            ->get('/admin/update/download?action=extract')
+            ->see('No file available');
+
+        file_put_contents(storage_path('update_cache/update.zip'), 'text');
+        $this->withSession(['tmp_path' => storage_path('update_cache/update.zip')])
+            ->get('/admin/update/download?action=extract')
+            ->see(trans('admin.update.errors.unzip'));
+
+        copy(
+            storage_path('testing/update.zip'),
+            storage_path('update_cache/update.zip')
+        );
+        $this->get('/admin/update/download?action=extract')
+            ->see(trans('admin.update.complete'));
+
+
+        mkdir(storage_path('update_cache'));
+        copy(
+            storage_path('testing/update.zip'),
+            storage_path('update_cache/update.zip')
+        );
+        File::shouldReceive('copyDirectory')
+            ->with(storage_path('update_cache/4.0.0/vendor'), base_path('vendor'))
+            ->andThrow(new \Exception);
+        File::shouldReceive('deleteDirectory')
+            ->with(storage_path('update_cache/4.0.0/vendor'));
+        $this->get('/admin/update/download?action=extract');
+
+
+        File::shouldReceive('copyDirectory')
+            ->with(storage_path('update_cache/4.0.0'), base_path())
+            ->andThrow(new Exception);
+        File::shouldReceive('deleteDirectory')
+            ->with(storage_path('update_cache'));
+        File::shouldReceive('deleteDirectory')
+            ->with(storage_path('update_cache'));
+        $this->get('/admin/update/download?action=extract')
+            ->see(trans('admin.update.errors.overwrite'));
+
+        // Invalid action
+        $this->get('/admin/update/download?action=no')
+            ->seeJson([
+                'errno' => 1,
+                'msg' => trans('general.illegal-parameters')
+            ]);
+    }
+}