Feat/hilo counter

src/Domain/HiLoCounter.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Domain;
+
+final class HiLoCounter
+{
+    private int $count = 0;
+
+    public function count(Card $card): void
+    {
+        $value = $card->numericValue();
+
+        if ($value >= 2 && $value <= 6) {
+            $this->count++;
+        } elseif ($value >= 10) {
+            $this->count--;
+        }
+    }
+
+    public function runningCount(): int
+    {
+        return $this->count;
+    }
+
+    public function reset(): void
+    {
+        $this->count = 0;
+    }
+}

tests/Domain/BasicStrategyTest.php

@@ -516,4 +516,17 @@ public function testPairOf10sShouldNotSplit(): void
 
         $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf9sAgainstDealerTenShouldStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('9', 'Hearts'));
+        $hand->addCard(new Card('9', 'Spades'));
+
+        $dealerCard = new Card('10', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
 }

tests/Domain/HiLoCounterTest.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace App\Tests\Domain;
+
+use App\Domain\Card;
+use App\Domain\HiLoCounter;
+use PHPUnit\Framework\TestCase;
+
+final class HiLoCounterTest extends TestCase
+{
+    public function testLowCardIncrementsCount(): void
+    {
+        $counter = new HiLoCounter();
+        $counter->count(new Card('5', 'Hearts'));
+
+        $this->assertSame(1, $counter->runningCount());
+    }
+
+    public function testNeutralCardDoesNotChangeCount(): void
+    {
+        $counter = new HiLoCounter();
+        $counter->count(new Card('7', 'Hearts'));
+
+        $this->assertSame(0, $counter->runningCount());
+    }
+
+    public function testHighCardDecrementsCount(): void
+    {
+        $counter = new HiLoCounter();
+        $counter->count(new Card('King', 'Hearts'));
+
+        $this->assertSame(-1, $counter->runningCount());
+    }
+
+    public function testMultipleCardsAccumulateCount(): void
+    {
+        $counter = new HiLoCounter();
+        $counter->count(new Card('2', 'Hearts'));
+        $counter->count(new Card('King', 'Spades'));
+        $counter->count(new Card('5', 'Diamonds'));
+        $counter->count(new Card('7', 'Clubs'));
+
+        $this->assertSame(1, $counter->runningCount());
+    }
+
+    public function testResetCounterReturnsToZero(): void
+    {
+        $counter = new HiLoCounter();
+        $counter->count(new Card('2', 'Hearts'));
+        $counter->count(new Card('3', 'Spades'));
+        $counter->reset();
+
+        $this->assertSame(0, $counter->runningCount());
+    }
+}