From afb802bdb0ce7cf472222350e3ec1105af625976 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:10:10 +0200
Subject: [PATCH 01/12] feat: Hand detects pair

---
 src/Domain/Hand.php       | 6 ++++++
 tests/Domain/HandTest.php | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/Domain/Hand.php b/src/Domain/Hand.php
index 2177526..20e537a 100644
--- a/src/Domain/Hand.php
+++ b/src/Domain/Hand.php
@@ -57,4 +57,10 @@ public function isSoft(): bool
 
         return $aces > 0 && $total <= 21;
     }
+
+    public function isPair(): bool
+    {
+        return count($this->cards) === 2
+            && $this->cards[0]->rank() === $this->cards[1]->rank();
+    }
 }
diff --git a/tests/Domain/HandTest.php b/tests/Domain/HandTest.php
index 146f465..dee878d 100644
--- a/tests/Domain/HandTest.php
+++ b/tests/Domain/HandTest.php
@@ -70,4 +70,13 @@ public function testHandWithAceCountedAs11IsSoft(): void
 
         $this->assertTrue($hand->isSoft());
     }
+
+    public function testHandWithTwoIdenticalRanksIsPair(): void
+    {
+        $hand = new Hand();
+        $hand->addCard(new Card('8', 'Hearts'));
+        $hand->addCard(new Card('8', 'Spades'));
+
+        $this->assertTrue($hand->isPair());
+    }
 }

From babb4d21d1bdbb74d82bf745fb59382d9730480e Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:10:47 +0200
Subject: [PATCH 02/12] test: hand with different ranks is not a pair

---
 tests/Domain/HandTest.php | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tests/Domain/HandTest.php b/tests/Domain/HandTest.php
index dee878d..579a18d 100644
--- a/tests/Domain/HandTest.php
+++ b/tests/Domain/HandTest.php
@@ -79,4 +79,13 @@ public function testHandWithTwoIdenticalRanksIsPair(): void
 
         $this->assertTrue($hand->isPair());
     }
+
+    public function testHandWithDifferentRanksIsNotPair(): void
+    {
+        $hand = new Hand();
+        $hand->addCard(new Card('8', 'Hearts'));
+        $hand->addCard(new Card('9', 'Spades'));
+
+        $this->assertFalse($hand->isPair());
+    }
 }

From 6bfb750c4d8f77bf3b9f6e8f4f732c2271ec0d2c Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:13:52 +0200
Subject: [PATCH 03/12] feat: Hand returns pair rank

---
 src/Domain/Hand.php       | 5 +++++
 tests/Domain/HandTest.php | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/Domain/Hand.php b/src/Domain/Hand.php
index 20e537a..05b0fc9 100644
--- a/src/Domain/Hand.php
+++ b/src/Domain/Hand.php
@@ -63,4 +63,9 @@ public function isPair(): bool
         return count($this->cards) === 2
             && $this->cards[0]->rank() === $this->cards[1]->rank();
     }
+
+    public function pairRank(): string
+    {
+        return $this->cards[0]->rank();
+    }
 }
diff --git a/tests/Domain/HandTest.php b/tests/Domain/HandTest.php
index 579a18d..4b0df49 100644
--- a/tests/Domain/HandTest.php
+++ b/tests/Domain/HandTest.php
@@ -88,4 +88,13 @@ public function testHandWithDifferentRanksIsNotPair(): void
 
         $this->assertFalse($hand->isPair());
     }
+
+    public function testPairRankReturnsCardRank(): void
+    {
+        $hand = new Hand();
+        $hand->addCard(new Card('8', 'Hearts'));
+        $hand->addCard(new Card('8', 'Spades'));
+
+        $this->assertSame('8', $hand->pairRank());
+    }
 }

From 0486eb32cf5e2e3392033e8af81be57233ac66f0 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:17:05 +0200
Subject: [PATCH 04/12] feat: BasicStrategy splits Aces and 8s always

---
 src/Domain/BasicStrategy.php       |  8 ++++++++
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index 7d0f2e9..bfa87f6 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -9,6 +9,14 @@ public function decide(Hand $hand, Card $dealerCard): Decision
         $value = $hand->value();
         $dealerValue = $dealerCard->numericValue();
 
+        if ($hand->isPair()) {
+            $rank = $hand->pairRank();
+
+            if ($rank === 'Ace' || $rank === '8') {
+                return Decision::Split;
+            }
+        }
+
         if ($hand->isSoft() && $value === 18) {
             if ($dealerValue >= 3 && $dealerValue <= 6) {
                 return Decision::Double;
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index eeaa732..ac059f9 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -386,4 +386,17 @@ public function testHard16AgainstDealer7ShouldHit(): void
 
         $this->assertSame(Decision::Hit, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf8sShouldAlwaysSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('8', 'Hearts'));
+        $hand->addCard(new Card('8', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From 72520e905d4a0053020eb88163e2ca22c3d24b58 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:23:09 +0200
Subject: [PATCH 05/12] feat: BasicStrategy splits 9s against dealer 2-9 except
 7

---
 src/Domain/BasicStrategy.php       |  4 ++++
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index bfa87f6..2f7c747 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -15,6 +15,10 @@ public function decide(Hand $hand, Card $dealerCard): Decision
             if ($rank === 'Ace' || $rank === '8') {
                 return Decision::Split;
             }
+
+            if ($rank === '9' && !in_array($dealerValue, [7, 10, 11], true)) {
+                return Decision::Split;
+            }
         }
 
         if ($hand->isSoft() && $value === 18) {
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index ac059f9..f63b9f3 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -399,4 +399,17 @@ public function testPairOf8sShouldAlwaysSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf9sAgainstDealer6ShouldSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('9', 'Hearts'));
+        $hand->addCard(new Card('9', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From d0278900943885dd26eb62272dead4ccb7d3e267 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:24:00 +0200
Subject: [PATCH 06/12] test: pair of 9s against dealer 7 should stand

---
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index f63b9f3..acf972a 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -412,4 +412,17 @@ public function testPairOf9sAgainstDealer6ShouldSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf9sAgainstDealer7ShouldStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('9', 'Hearts'));
+        $hand->addCard(new Card('9', 'Spades'));
+
+        $dealerCard = new Card('7', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From 3f374d03e1d3b58bb2680bee703386e52ccee985 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:27:42 +0200
Subject: [PATCH 07/12] feat: BasicStrategy splits 7s against dealer 2-7

---
 src/Domain/BasicStrategy.php       |  4 ++++
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index 2f7c747..acd658b 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -19,6 +19,10 @@ public function decide(Hand $hand, Card $dealerCard): Decision
             if ($rank === '9' && !in_array($dealerValue, [7, 10, 11], true)) {
                 return Decision::Split;
             }
+
+            if ($rank === '7' && $dealerValue >= 2 && $dealerValue <= 7) {
+                return Decision::Split;
+            }
         }
 
         if ($hand->isSoft() && $value === 18) {
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index acf972a..c1638a0 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -425,4 +425,17 @@ public function testPairOf9sAgainstDealer7ShouldStand(): void
 
         $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf7sAgainstDealer5ShouldSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('7', 'Hearts'));
+        $hand->addCard(new Card('7', 'Spades'));
+
+        $dealerCard = new Card('5', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From b52285a7982e05a98b97716606624445acef94f7 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:29:39 +0200
Subject: [PATCH 08/12] feat: BasicStrategy splits 6s against dealer 2-6

---
 src/Domain/BasicStrategy.php       |  4 ++++
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index acd658b..be050a6 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -23,6 +23,10 @@ public function decide(Hand $hand, Card $dealerCard): Decision
             if ($rank === '7' && $dealerValue >= 2 && $dealerValue <= 7) {
                 return Decision::Split;
             }
+
+            if ($rank === '6' && $dealerValue >= 2 && $dealerValue <= 6) {
+                return Decision::Split;
+            }
         }
 
         if ($hand->isSoft() && $value === 18) {
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index c1638a0..213893d 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -438,4 +438,17 @@ public function testPairOf7sAgainstDealer5ShouldSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf6sAgainstDealer4ShouldSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('6', 'Hearts'));
+        $hand->addCard(new Card('6', 'Spades'));
+
+        $dealerCard = new Card('4', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From f9428f052bdf418de397a100540271d8082548b4 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:33:02 +0200
Subject: [PATCH 09/12] feat: BasicStrategy splits 4s against dealer 5-6

---
 src/Domain/BasicStrategy.php       |  4 ++++
 tests/Domain/BasicStrategyTest.php | 17 +++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index be050a6..d22f7c7 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -27,6 +27,10 @@ public function decide(Hand $hand, Card $dealerCard): Decision
             if ($rank === '6' && $dealerValue >= 2 && $dealerValue <= 6) {
                 return Decision::Split;
             }
+
+            if ($rank === '4' && $dealerValue >= 5 && $dealerValue <= 6) {
+                return Decision::Split;
+            }
         }
 
         if ($hand->isSoft() && $value === 18) {
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index 213893d..d902239 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -340,8 +340,8 @@ public function testHard8ShouldAlwaysHit(): void
         $strategy = new BasicStrategy();
 
         $hand = new Hand();
-        $hand->addCard(new Card('4', 'Hearts'));
-        $hand->addCard(new Card('4', 'Spades'));
+        $hand->addCard(new Card('5', 'Hearts'));
+        $hand->addCard(new Card('3', 'Spades'));
 
         $dealerCard = new Card('6', 'Diamonds');
 
@@ -451,4 +451,17 @@ public function testPairOf6sAgainstDealer4ShouldSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf4sAgainstDealer5ShouldSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('4', 'Hearts'));
+        $hand->addCard(new Card('4', 'Spades'));
+
+        $dealerCard = new Card('5', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From af09e327085abf9abec3686b1081972492e16f87 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:34:24 +0200
Subject: [PATCH 10/12] feat: BasicStrategy splits 3s against dealer 2-7

---
 src/Domain/BasicStrategy.php       |  4 ++++
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index d22f7c7..6cc1bfd 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -31,6 +31,10 @@ public function decide(Hand $hand, Card $dealerCard): Decision
             if ($rank === '4' && $dealerValue >= 5 && $dealerValue <= 6) {
                 return Decision::Split;
             }
+
+            if ($rank === '3' && $dealerValue >= 2 && $dealerValue <= 7) {
+                return Decision::Split;
+            }
         }
 
         if ($hand->isSoft() && $value === 18) {
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index d902239..dd0182b 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -464,4 +464,17 @@ public function testPairOf4sAgainstDealer5ShouldSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf3sAgainstDealer4ShouldSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('3', 'Hearts'));
+        $hand->addCard(new Card('3', 'Spades'));
+
+        $dealerCard = new Card('4', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From faba9b0fa95c82d90e6f27c3fdf6ed562a49b410 Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:35:37 +0200
Subject: [PATCH 11/12] feat: BasicStrategy splits 2s against dealer 2-7

---
 src/Domain/BasicStrategy.php       |  4 ++++
 tests/Domain/BasicStrategyTest.php | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Domain/BasicStrategy.php b/src/Domain/BasicStrategy.php
index 6cc1bfd..49335d3 100644
--- a/src/Domain/BasicStrategy.php
+++ b/src/Domain/BasicStrategy.php
@@ -35,6 +35,10 @@ public function decide(Hand $hand, Card $dealerCard): Decision
             if ($rank === '3' && $dealerValue >= 2 && $dealerValue <= 7) {
                 return Decision::Split;
             }
+
+            if ($rank === '2' && $dealerValue >= 2 && $dealerValue <= 7) {
+                return Decision::Split;
+            }
         }
 
         if ($hand->isSoft() && $value === 18) {
diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index dd0182b..de7908c 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -477,4 +477,17 @@ public function testPairOf3sAgainstDealer4ShouldSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf2sAgainstDealer4ShouldSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('2', 'Hearts'));
+        $hand->addCard(new Card('2', 'Spades'));
+
+        $dealerCard = new Card('4', 'Diamonds');
+
+        $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file

From f0d38b9c5742d6c4df2c34b98794b4b8508a06eb Mon Sep 17 00:00:00 2001
From: florentdevk <florentdevk@gmail.com>
Date: Tue, 23 Jun 2026 20:36:27 +0200
Subject: [PATCH 12/12] test: pair of 5s and 10s should not split

---
 tests/Domain/BasicStrategyTest.php | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/tests/Domain/BasicStrategyTest.php b/tests/Domain/BasicStrategyTest.php
index de7908c..c2802da 100644
--- a/tests/Domain/BasicStrategyTest.php
+++ b/tests/Domain/BasicStrategyTest.php
@@ -490,4 +490,30 @@ public function testPairOf2sAgainstDealer4ShouldSplit(): void
 
         $this->assertSame(Decision::Split, $strategy->decide($hand, $dealerCard));
     }
+
+    public function testPairOf5sShouldNotSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('5', 'Hearts'));
+        $hand->addCard(new Card('5', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Double, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testPairOf10sShouldNotSplit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('10', 'Hearts'));
+        $hand->addCard(new Card('10', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
 }
\ No newline at end of file