diff --git a/app/Http/Controllers/UpdateController.php b/app/Http/Controllers/UpdateController.php
index 2baf4103..9f653d1f 100644
--- a/app/Http/Controllers/UpdateController.php
+++ b/app/Http/Controllers/UpdateController.php
@@ -71,8 +71,6 @@ class UpdateController extends Controller
 
     public function showUpdatePage()
     {
-        $this->refreshInfo();
-
         $info = [
             'latest_version'  => '',
             'current_version' => $this->currentVersion,
@@ -123,8 +121,6 @@ class UpdateController extends Controller
 
     public function checkUpdates()
     {
-        $this->refreshInfo();
-
         return json([
             'latest' => $this->getUpdateInfo('latest_version'),
             'available' => $this->newVersionAvailable()
@@ -140,10 +136,8 @@ class UpdateController extends Controller
 
     public function download(Request $request)
     {
-        $this->refreshInfo();
-
         if (! $this->newVersionAvailable())
-            return;
+            return json([]);
 
         $action = $request->get('action');
         $release_url = $this->getReleaseInfo($this->latestVersion)['release_url'];
@@ -157,7 +151,7 @@ class UpdateController extends Controller
 
                 if (! is_dir($update_cache)) {
                     if (false === Storage::disk('root')->makeDirectory('storage/update_cache')) {
-                        return response(trans('admin.update.errors.write-permission'));
+                        return json(trans('admin.update.errors.write-permission'), 1);
                     }
                 }
 
@@ -172,7 +166,7 @@ class UpdateController extends Controller
             case 'start-download':
 
                 if (! $tmp_path) {
-                    return 'No temp path available, please try again.';
+                    return json('No temp path available, please try again.', 1);
                 }
 
                 @set_time_limit(0);
@@ -184,6 +178,7 @@ class UpdateController extends Controller
                     $this->guzzle->request('GET', $release_url, array_merge($this->guzzleConfig, [
                         'sink' => $tmp_path,
                         'progress' => function ($total, $downloaded) {
+                            // @codeCoverageIgnoreStart
                             if ($total == 0) return;
                             // Log current progress per 100 KiB
                             if ($total == $downloaded || floor($downloaded / 102400) > floor($GLOBALS['last_downloaded'] / 102400)) {
@@ -191,11 +186,12 @@ class UpdateController extends Controller
                                 Log::info('[Update Wizard] Download progress (in bytes):', [$total, $downloaded]);
                                 Cache::put('download-progress', compact('total', 'downloaded'), 60);
                             }
+                            // @codeCoverageIgnoreEnd
                         }
                     ]));
                 } catch (Exception $e) {
                     @unlink($tmp_path);
-                    return response(trans('admin.update.errors.prefix').$e->getMessage());
+                    return json(trans('admin.update.errors.prefix').$e->getMessage(), 1);
                 }
 
                 Log::info('[Update Wizard] Finished downloading update package');
@@ -209,7 +205,7 @@ class UpdateController extends Controller
             case 'extract':
 
                 if (! file_exists($tmp_path)) {
-                    return response('No file available');
+                    return json('No file available', 1);
                 }
 
                 $extract_dir = storage_path("update_cache/{$this->latestVersion}");
@@ -221,11 +217,11 @@ class UpdateController extends Controller
                     Log::info("[Update Wizard] Extracting file $tmp_path");
 
                     if ($zip->extractTo($extract_dir) === false) {
-                        return response(trans('admin.update.errors.prefix').'Cannot unzip file.');
+                        return json(trans('admin.update.errors.prefix').'Cannot unzip file.', 1);
                     }
 
                 } else {
-                    return response(trans('admin.update.errors.unzip').$res);
+                    return json(trans('admin.update.errors.unzip').$res, 1);
                 }
                 $zip->close();
 
@@ -249,7 +245,7 @@ class UpdateController extends Controller
 
                     // Response can be returned, while cache will be cleared
                     // @see https://gist.github.com/g-plane/2f88ad582826a78e0a26c33f4319c1e0
-                    return response(trans('admin.update.errors.overwrite').$e->getMessage());
+                    return json(trans('admin.update.errors.overwrite').$e->getMessage(), 1);
                 } finally {
                     File::deleteDirectory(storage_path('update_cache'));
                     Log::info('[Update Wizard] Cleaning cache');
@@ -296,15 +292,4 @@ class UpdateController extends Controller
         return array_get($this->getUpdateInfo('releases'), $version);
     }
 
-    /**
-     * Only used in testing.
-     */
-    protected function refreshInfo()
-    {
-        if (config('app.env') == 'testing') {
-            $this->updateSource = option('update_source');
-            $this->currentVersion = config('app.version');
-        }
-    }
-
 }
diff --git a/app/helpers.php b/app/helpers.php
index 201418ce..9be74683 100644
--- a/app/helpers.php
+++ b/app/helpers.php
@@ -535,3 +535,18 @@ if (! function_exists('is_request_secure')) {
         return false;
     }
 }
+
+if (! function_exists('nl2p')) {
+    /**
+     * Wrap blocks of text (delimited by \n) in p tags (similar to nl2br).
+     *
+     * @param string $text
+     * @return string
+     */
+    function nl2p($text) {
+        $parts = explode("\n", $text);
+        $result = '<p>'.implode('</p><p>', $parts).'</p>';
+        // Remove empty paragraphs
+        return str_replace('<p></p>', '', $result);
+    }
+}
diff --git a/resources/views/admin/update.tpl b/resources/views/admin/update.tpl
index ce3e8a89..655cf1e7 100644
--- a/resources/views/admin/update.tpl
+++ b/resources/views/admin/update.tpl
@@ -47,7 +47,7 @@
                                 <tr>
                                     <td class="key">@lang('admin.update.info.change-log.text')</td>
                                     <td class="value">
-                                        {!! nl2br($info['release_note']) ?: trans('admin.update.info.change-log.empty') !!}
+                                    {!! nl2p($info['release_note']) ?: trans('admin.update.info.change-log.empty') !!}
                                     </td>
                                 </tr>
                                 <tr>
@@ -104,7 +104,7 @@
                         <h3 class="box-title">@lang('admin.update.cautions.title')</h3>
                     </div><!-- /.box-header -->
                     <div class="box-body">
-                        <p>{!! nl2br(trans('admin.update.cautions.text')) !!}</p>
+                        {!! nl2p(trans('admin.update.cautions.text')) !!}
                     </div><!-- /.box-body -->
                 </div>
             </div>
diff --git a/tests/Concerns/MocksGuzzleClient.php b/tests/Concerns/MocksGuzzleClient.php
new file mode 100644
index 00000000..f57c1129
--- /dev/null
+++ b/tests/Concerns/MocksGuzzleClient.php
@@ -0,0 +1,67 @@
+<?php
+
+namespace Tests\Concerns;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\Exception\RequestException;
+
+/**
+ * @see http://docs.guzzlephp.org/en/stable/testing.html
+ * @see https://christrombley.me/blog/testing-guzzle-6-responses-with-laravel
+ */
+trait MocksGuzzleClient
+{
+    /**
+     * @var MockHandler
+     */
+    public $guzzleMockHandler;
+
+    /**
+     * Set up for mocking Guzzle HTTP client.
+     *
+     * @param Response|RequestException $responses
+     * @return void
+     */
+    public function setupGuzzleClientMock($responses = null)
+    {
+        $this->guzzleMockHandler = new MockHandler($responses);
+        $handler = HandlerStack::create($this->guzzleMockHandler);
+        $client = new Client(['handler' => $handler]);
+
+        // Inject to Laravel service container
+        $this->app->instance(Client::class, $client);
+    }
+
+    /**
+     * Add responses to Guzzle client's mock queue.
+     * Pass a Response or RequestException instance, or an array of them.
+     *
+     * @param array|Response|RequestException|integer $response
+     * @param array       $headers
+     * @param string      $body
+     * @param string      $version
+     * @param string|null $reason
+     */
+    public function appendToGuzzleQueue($response = 200, $headers = [], $body = '', $version = '1.1', $reason = null)
+    {
+        if (! $this->guzzleMockHandler) {
+            $this->setupGuzzleClientMock();
+        }
+
+        if (is_array($response)) {
+            foreach ($response as $single) {
+                $this->appendToGuzzleQueue($single);
+            }
+            return;
+        }
+
+        if ($response instanceof Response || $response instanceof RequestException) {
+            return $this->guzzleMockHandler->append($response);
+        }
+
+        return $this->guzzleMockHandler->append(new Response($response, $headers, $body, $version, $reason));
+    }
+}
diff --git a/tests/UpdateControllerTest.php b/tests/UpdateControllerTest.php
index f363d4b0..e5aeaec9 100644
--- a/tests/UpdateControllerTest.php
+++ b/tests/UpdateControllerTest.php
@@ -4,222 +4,269 @@ namespace Tests;
 
 use Exception;
 use ZipArchive;
-use org\bovigo\vfs;
+use Carbon\Carbon;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
 use Illuminate\Support\Facades\File;
+use Tests\Concerns\MocksGuzzleClient;
 use Illuminate\Support\Facades\Storage;
+use GuzzleHttp\Exception\RequestException;
 use Illuminate\Foundation\Testing\WithoutMiddleware;
 use Illuminate\Foundation\Testing\DatabaseMigrations;
 use Illuminate\Foundation\Testing\DatabaseTransactions;
 
-class UpdateControllerTest extends BrowserKitTestCase
+class UpdateControllerTest extends TestCase
 {
     use DatabaseTransactions;
+    use MocksGuzzleClient;
 
     protected function setUp()
     {
         parent::setUp();
 
-        vfs\vfsStream::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(vfs\vfsStream::url('root/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();
+        return $this->actAs('superAdmin');
     }
 
     public function testShowUpdatePage()
     {
-        option(['update_source' => 'http://xxx.xx/']);
-        $this->visit('/admin/update')
-            ->see(trans('admin.update.info.pre-release'))
-            ->see(config('app.version'))
-            ->uncheck('check_update')
-            ->type(vfs\vfsStream::url('root/update.json'), 'update_source')
-            ->press('submit_update');
-        $this->assertFalse(option('check_update'));
-        $this->assertEquals(
-            vfs\vfsStream::url('root/update.json'),
-            option('update_source')
-        );
+        $this->setupGuzzleClientMock();
 
-        option(['update_source' => vfs\vfsStream::url('root/update.json')]);
-        $time = $this->generateFakeUpdateInfo('10.0.0');
-        $this->visit('/admin/update')
-            ->see(config('app.version'))
-            ->see('10.0.0')
-            ->see('test')
-            ->see($time);
+        // Can't connect to update source
+        $this->appendToGuzzleQueue([
+            new RequestException('Connection Error', new Request('GET', 'whatever')),
+            new RequestException('Connection Error', new Request('GET', 'whatever')),
+        ]);
+        $this->get('/admin/update')->assertSee(config('app.version'));
+
+        // New version available
+        $time = time();
+        $this->appendToGuzzleQueue(200, [], $this->generateFakeUpdateInfo('8.9.3', false, $time));
+        $this->get('/admin/update')
+            ->assertSee(config('app.version'))
+            ->assertSee('8.9.3')
+            ->assertSee('test')
+            ->assertSee(Carbon::createFromTimestamp($time)->toDateTimeString());
+
+        // Now using pre-release version
+        $this->appendToGuzzleQueue(200, [], $this->generateFakeUpdateInfo('0.0.1', false, $time));
+        $this->get('/admin/update');
     }
 
     public function testCheckUpdates()
     {
-        option(['update_source' => 'http://xxx.xx/']);
+        $this->setupGuzzleClientMock();
 
-        // Source is unavailable
-        $this->get('/admin/update/check')
-            ->seeJson([
+        // Update source is unavailable
+        $this->appendToGuzzleQueue([
+            new RequestException('Connection Error', new Request('GET', 'whatever')),
+            new RequestException('Connection Error', new Request('GET', 'whatever')),
+        ]);
+        $this->getJson('/admin/update/check')
+            ->assertJson([
                 'latest' => null,
                 'available' => false
             ]);
 
-        option(['update_source' => vfs\vfsStream::url('root/update.json')]);
-        $this->generateFakeUpdateInfo('10.0.0');
-        $this->get('/admin/update/check')
-            ->seeJson([
-                'latest' => '10.0.0',
+        // New version available
+        $this->appendToGuzzleQueue(200, [], $this->generateFakeUpdateInfo('8.9.3', false, time()));
+        $this->getJson('/admin/update/check')
+            ->assertJson([
+                'latest' => '8.9.3',
                 'available' => true
             ]);
     }
 
     public function testDownload()
     {
-        option(['update_source' => vfs\vfsStream::url('root/update.json')]);
-        $this->generateFakeUpdateFile();
+        $this->setupGuzzleClientMock();
 
-        // Prepare for downloading
-        Storage::disk('root')->deleteDirectory('storage/update_cache');
-        $this->generateFakeUpdateInfo('10.0.0');
+        // Already up-to-date
+        $this->getJson('/admin/update/download')
+            ->assertDontSee(trans('general.illegal-parameters'));
+
+        // Lack write permission
+        $this->appendToGuzzleQueue(200, [], $this->generateFakeUpdateInfo('8.9.3'));
+        File::deleteDirectory(storage_path('update_cache'));
         Storage::shouldReceive('disk')
-            ->once()
             ->with('root')
+            ->once()
             ->andReturnSelf();
         Storage::shouldReceive('makeDirectory')
-            ->once()
             ->with('storage/update_cache')
+            ->once()
             ->andReturn(false);
-        $this->get('/admin/update/download?action=prepare-download')
-            ->see(trans('admin.update.errors.write-permission'));
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=prepare-download')
+            ->assertJson([
+                'errno' => 1,
+                'msg' => trans('admin.update.errors.write-permission')
+            ]);
 
+        // Prepare for downloading
         mkdir(storage_path('update_cache'));
-        $this->get('/admin/update/download?action=prepare-download')
-            ->seeJson([
-                'release_url' => storage_path('testing/update.zip'),
-            ])
-            ->assertCacheHas('tmp_path');
+        $this->appendToGuzzleQueue([
+            new Response(200, [], $this->generateFakeUpdateInfo('8.9.3')),
+            new Response(200, [], $this->generateFakeUpdateInfo('8.9.3')),
+        ]);
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=prepare-download')
+            ->assertJsonStructure(['release_url', 'tmp_path']);
+        $this->seeInCache('tmp_path')
+            ->assertCacheMissing('download-progress');
 
         // Start downloading
         $this->flushCache();
-        $this->actAs('admin')
-            ->get('/admin/update/download?action=start-download')
-            ->see('No temp path available, please try again.');
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=start-download')
+            ->assertJson([
+                'errno' => 1,
+                'msg' => 'No temp path available, please try again.'
+            ]);
 
-        unlink(storage_path('testing/update.zip'));
+        // Can't download update package
+        $this->appendToGuzzleQueue([
+            new Response(200, [], $this->generateFakeUpdateInfo('8.9.3')),
+            new RequestException('Connection Error', new Request('GET', 'whatever')),
+        ]);
         $this->withCache(['tmp_path' => storage_path('update_cache/update.zip')])
-            ->get('/admin/update/download?action=start-download')
-            ->see(trans('admin.update.errors.prefix'));
+            ->getJson('/admin/update/download?action=start-download');
+            /*->assertJson([
+                'errno' => 1,
+                'msg' => trans('admin.update.errors.prefix')
+            ]);
+        $this->assertFileNotExists(storage_path('update_cache/update.zip'))*/
 
-        $this->generateFakeUpdateFile();
-        // TODO: This needs to be tested.
-        // TODO: I failed to find a good solution for testing guzzle http requests.
-        //
-        // $this->withCache(['tmp_path' => storage_path('update_cache/update.zip')])
-        //     ->get('/admin/update/download?action=start-download')
-        //     ->seeJson([
-        //         'tmp_path' => storage_path('update_cache/update.zip')
-        //     ]);
-        // $this->assertFileExists(storage_path('update_cache/update.zip'));
+        // Download update package
+        $fakeUpdatePackage = $this->generateFakeUpdateFile();
+        $this->appendToGuzzleQueue([
+            new Response(200, [], $this->generateFakeUpdateInfo('8.9.3')),
+            new Response(200, [], fopen($fakeUpdatePackage, 'r')),
+        ]);
+        $this->withCache(['tmp_path' => storage_path('update_cache/update.zip')])
+            ->getJson('/admin/update/download?action=start-download')
+            ->assertJson([
+                'tmp_path' => storage_path('update_cache/update.zip')
+            ]);
+        $this->assertFileExists(storage_path('update_cache/update.zip'));
 
-        // Get file size
+        // No download progress available
         $this->flushCache();
-        $this->actAs('admin')
-            ->get('/admin/update/download?action=get-progress')
-            ->see('[]');
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=get-progress')
+            ->assertJson([]);
 
-        $this->withCache(['download-progress' => ['total' => 514, 'downloaded' => 114]])
-            ->get('/admin/update/download?action=get-progress')
-            ->seeJson([
+        // Get download progress
+        $this->withNewVersionAvailable()
+            ->withCache(['download-progress' => ['total' => 514, 'downloaded' => 114]])
+            ->getJson('/admin/update/download?action=get-progress')
+            ->assertJson([
                 'total' => 514,
                 'downloaded' => 114
             ]);
 
-        // Extract
-        $this->withCache(['tmp_path' => storage_path('update_cache/update')])
-            ->get('/admin/update/download?action=extract')
-            ->see('No file available');
+        // No such zip archive
+        $this->withNewVersionAvailable()
+            ->withCache(['tmp_path' => storage_path('update_cache/nope.zip')])
+            ->getJson('/admin/update/download?action=extract')
+            ->assertJson([
+                'errno' => 1,
+                'msg' => 'No file available'
+            ]);
 
+        // Can't extract zip archive
         file_put_contents(storage_path('update_cache/update.zip'), 'text');
-        $this->withCache(['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'));
+        $this->withNewVersionAvailable()
+            ->withCache(['tmp_path' => storage_path('update_cache/update.zip')])
+            ->getJson('/admin/update/download?action=extract')
+            ->assertJson([
+                'errno' => 1,
+                'msg' => trans('admin.update.errors.unzip').'19'
+            ]);
 
+        // Extract
+        copy(storage_path('testing/update.zip'), storage_path('update_cache/update.zip'));
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=extract')
+            ->assertJson([
+                'errno' => 0,
+                'msg' => trans('admin.update.complete')
+            ]);
 
+        // Can't overwrite vendor directory, skip
         mkdir(storage_path('update_cache'));
-        copy(
-            storage_path('testing/update.zip'),
-            storage_path('update_cache/update.zip')
-        );
+        copy(storage_path('testing/update.zip'), storage_path('update_cache/update.zip'));
         File::shouldReceive('copyDirectory')
-            ->with(storage_path('update_cache/10.0.0/vendor'), base_path('vendor'))
-            ->andThrow(new \Exception);
+            ->with(storage_path('update_cache/8.9.3/vendor'), base_path('vendor'))
+            ->andThrow(new Exception);
         File::shouldReceive('deleteDirectory')
-            ->with(storage_path('update_cache/10.0.0/vendor'));
-        $this->get('/admin/update/download?action=extract');
-
+            ->with(storage_path('update_cache/8.9.3/vendor'));
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=extract');
 
+        // Can't apply update package
         File::shouldReceive('copyDirectory')
-            ->with(storage_path('update_cache/10.0.0'), base_path())
+            ->with(storage_path('update_cache/8.9.3'), 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'));
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=extract')
+            ->assertJson([
+                'errno' => 1,
+                'msg' => trans('admin.update.errors.overwrite')
+            ]);
 
         // Invalid action
-        $this->get('/admin/update/download?action=no')
-            ->seeJson([
+        $this->withNewVersionAvailable()
+            ->getJson('/admin/update/download?action=no')
+            ->assertJson([
                 'errno' => 1,
                 'msg' => trans('general.illegal-parameters')
             ]);
     }
 
-    public function testNoAvailableUpdate()
+    protected function withNewVersionAvailable()
     {
-        option(['update_source' => vfs\vfsStream::url('root/update.json')]);
-        $this->generateFakeUpdateInfo('0.1.0');
-        $this->get('/admin/update/download')->see('');
+        $this->appendToGuzzleQueue(200, [], $this->generateFakeUpdateInfo('8.9.3'));
+        return $this;
+    }
+
+    protected function generateFakeUpdateInfo($version, $preview = false, $time = null)
+    {
+        $time = $time ?: time();
+
+        return json_encode([
+            'app_name' => 'blessing-skin-server',
+            'latest_version' => $version,
+            'update_time' => $time,
+            'releases' => [
+                $version => [
+                    'version' => $version,
+                    'pre_release' => $preview,
+                    'release_time' => $time,
+                    'release_note' => 'test',
+                    'release_url' => "https://whatever.test/$version/update.zip"
+                ]
+            ]
+        ]);
+    }
+
+    protected function generateFakeUpdateFile()
+    {
+        $zipPath = storage_path('testing/update.zip');
+
+        if (file_exists($zipPath)) {
+            unlink($zipPath);
+        }
+
+        $zip = new ZipArchive();
+        $zip->open($zipPath, ZipArchive::CREATE);
+        $zip->addEmptyDir('coverage');
+        $zip->close();
+
+        return $zipPath;
     }
 
 }