Implement slugger unit test

tests/ConferenceSluggerTest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace App\Tests;
+
+use App\Entity\Conference;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\String\Slugger\SluggerInterface;
+
+
+class ConferenceSluggerTest extends KernelTestCase
+{
+    /**
+    * @dataProvider provideConferences
+    */
+    public function testConferenceComputeSlug(string $expectedResult, Conference $conference): void
+    {
+        self::bootKernel();
+        $slugger = static::getContainer()->get(SluggerInterface::class);
+
+        $conference->computeSlug($slugger);
+        $this->assertSame($expectedResult, $conference->getSlug());
+    }
+
+    public static function provideConferences(): iterable
+    {
+        $conference = new Conference();
+        $conference->setCity("Barcelona");
+        $conference->setyear("2002");
+        yield ["barcelona-2002", $conference];
+
+        $conference = new Conference();
+        $conference->setCity("Tokyo");
+        $conference->setyear("2020");
+        yield ["tokyo-2020", $conference];
+
+        $conference = new Conference();
+        $conference->setCity("Mexico City");
+        $conference->setyear("1999");
+        yield ["mexico-city-1999", $conference];
+    }
+}