Add day 6

tests/Day6Test.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Tests;
+
+use AdventOfCode21\Day6;
+
+/**
+ * @internal
+ */
+class Day6Test extends AbstractTestCase
+{
+    public static int $part1ExampleResult = 5934;
+    public static int $part1Result = 350917;
+
+    public static int $part2ExampleResult = 26984457539;
+    public static int $part2Result = 1592918715629;
+
+    public function setupDay(): Day6
+    {
+        return new class() extends Day6 {
+            use ReturnTestableResults;
+        };
+    }
+}