diff --git a/config/services_test.yaml b/config/services_test.yaml
new file mode 100644
index 0000000..38b9141
--- /dev/null
+++ b/config/services_test.yaml
@@ -0,0 +1,12 @@
+services:
+  # default configuration for services in *this* file
+  _defaults:
+    autowire: true      # Automatically injects dependencies in your services.
+    autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
+    public: true
+
+  App\Service\QRCodeGeneratorInterface:
+    lazy: true
+    public: true
+  # add more service definitions when explicit configuration is needed
+  # please note that last definitions always *replace* previous ones
diff --git a/tests/Controller/IndexControllerTest.php b/tests/Controller/IndexControllerTest.php
new file mode 100644
index 0000000..9f98168
--- /dev/null
+++ b/tests/Controller/IndexControllerTest.php
@@ -0,0 +1,92 @@
+<?php
+declare(strict_types=1);
+
+namespace App\Tests\Controller;
+
+use App\Service\QRCodeGeneratorInterface;
+use Symfony\Bundle\FrameworkBundle\KernelBrowser;
+use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
+
+class IndexControllerTest extends WebTestCase
+{
+    public function testFormIsPresentAfterLoadHomepage(): void
+    {
+        $client = static::createClient();
+        $client->request('GET', '/');
+
+        $this->assertResponseIsSuccessful();
+        $this->assertSelectorExists('form');
+    }
+
+    public function testImageIsPresentAfterSubmitForm(): void {
+        $client = $this->generateClientForSubmitTest();
+        $response = $client->request('GET', '/');
+        $this->assertResponseIsSuccessful();
+        $form = $response->selectButton('Vygenerovat QR kód')->form();
+        $dt = new \DateTime('now+1 hour'); // In case of 23:59:59
+        $client->submit($form, [
+            'qr_code' => [
+                    'iban' => 'CZ5508000000001234567899',
+                    'dueDate' => $dt->format('Y-m-d'),
+                    'message' => 'foo',
+                    'money' => [
+                        'currency' => 'CZK',
+                        'amount' => '100'
+                    ],
+                    'paymentIdentification' => [
+                        'variableSymbol' => '123',
+                        'constantSymbol' => '123',
+                        'specificSymbol' => '123'
+                    ]
+                ]
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertSelectorExists('form');
+        $this->assertSelectorExists('img');
+    }
+
+    public function testImageIsNotPresentAfterFailSubmitForm(): void {
+        $client = $this->generateClientForSubmitTest();
+        $response = $client->request('GET', '/');
+        $this->assertResponseIsSuccessful();
+        $form = $response->selectButton('Vygenerovat QR kód')->form();
+        $dt = new \DateTime('now+1 hour'); // In case of 23:59:59
+        $client->submit($form, [
+            'qr_code' => [
+                'iban' => 'IBAN_THAT_NOT_EXISTS',
+                'dueDate' => $dt->format('Y-m-d'),
+                'message' => 'foo',
+                'money' => [
+                    'currency' => 'CZK',
+                    'amount' => '100'
+                ],
+                'paymentIdentification' => [
+                    'variableSymbol' => '123',
+                    'constantSymbol' => '123',
+                    'specificSymbol' => '123'
+                ]
+            ]
+        ]);
+
+        $this->assertResponseIsUnprocessable();
+        $this->assertSelectorExists('form');
+        $this->assertSelectorNotExists('img');
+    }
+
+    private function generateClientForSubmitTest(): KernelBrowser
+    {
+        $mock = $this->createMock(QRCodeGeneratorInterface::class);
+        $mock->expects($this->any())
+            ->method('generateQRCodeFromEntity')
+            ->will($this->returnValue('foo'));
+
+
+        $client = static::createClient();
+        $client->disableReboot();
+
+        self::getContainer()->set('App\Service\QRCodeGeneratorInterface', $mock);
+
+        return $client;
+    }
+}