Add an initial test for counting past talks

composer.json

@@ -10,6 +10,7 @@
         }
     ],
     "require": {
+        "illuminate/collections": "^8.55",
         "opdavies/sculpin-gist-embed-bundle": "^0.1.0",
         "opdavies/sculpin-twig-markdown-bundle": "^0.2.0",
         "sculpin/sculpin": "^3.0"
@@ -22,5 +23,18 @@
     },
     "config": {
         "sort-packages": true
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^9.5"
+    },
+    "autoload": {
+        "psr-4": {
+            "App\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "App\\Tests\\": "tests/"
+        }
     }
 }

src/TwigExtension/TalkExtension.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\TwigExtension;
+
+use Illuminate\Support\Collection;
+
+final class TalkExtension
+{
+    public function getPastTalksCount(array $talks = []): int
+    {
+        $talkCollection = new Collection($talks);
+
+        return $talkCollection->count();
+    }
+}

tests/TalkExtensionTest.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Tests;
+
+use App\TwigExtension\TalkExtension;
+use PHPUnit\Framework\TestCase;
+
+final class TalkExtensionTest extends TestCase
+{
+    /** @test */
+    public function it_returns_zero_if_there_are_no_talks(): void
+    {
+        $this->assertSame(0, (new TalkExtension())->getPastTalksCount([]));
+    }
+}