fix: ensure HighCard only applies when no other combination matches

src/test/scala/combinations/HighCardTest.scala

@@ -5,7 +5,7 @@ import cards._
 
 class HighCardTest extends FunSuite {
 
-  test("HighCard accepts any hand") {
+  test("HighCard returns true only when no other combination applies") {
     val hand = List(
       Card(Two, Hearts),
       Card(Four, Clubs),
@@ -13,16 +13,21 @@ class HighCardTest extends FunSuite {
       Card(Jack, Spades),
       Card(Ace, Hearts)
     )
-
     val combination = HighCard()
-    assert(combination.verify(hand))
+    assert(combination.verify(hand)) // No other combination applies
     assertEquals(combination.score.chips, 5)
     assertEquals(combination.score.multiplier, 1)
   }
 
-  test("HighCard accepts even a single card") {
-    val hand = List(Card(King, Clubs))
+  test("HighCard returns false when hand has a pair") {
+    val hand = List(
+      Card(Two, Hearts),
+      Card(Two, Spades), // pair
+      Card(Four, Clubs),
+      Card(Six, Diamonds),
+      Card(Nine, Hearts)
+    )
     val combination = HighCard()
-    assert(combination.verify(hand))
+    assert(!combination.verify(hand)) // Because it's a pair
   }
 }