Moved score incrementation logic to Score class

src/main/java/scorekeeper/Score.java

@@ -11,4 +11,11 @@ public record Score(int a, int b) {
 		return a + ":" + b;
 	}
 
+	public Score aIncrementBy(int points) {
+		return new Score(a + points, b);
+	}
+
+	public Score bIncrementBy(int points) {
+		return new Score(a, b + points);
+	}
 }

src/main/java/scorekeeper/Team.java

@@ -4,12 +4,12 @@ public enum Team {
 	A {
 		@Override
 		Score score(Score oldScore, int points) {
-			return Score.ab(oldScore.a() + points, oldScore.b());
+			return oldScore.aIncrementBy(points);
 		}
 	}, B {
 		@Override
 		Score score(Score oldScore, int points) {
-			return Score.ab(oldScore.a(), oldScore.b() + points);
+			return oldScore.bIncrementBy(points);
 		}
 	}, NONE;
 

src/test/java/scorekeeper/ScoreTests.java

@@ -36,4 +36,18 @@ class ScoreTests {
 	void toStringDisplaysPointsSeparatedByColon() {
 		assertEquals("33:45", Score.ab(33, 45).toString());
 	}
+
+	@Test
+	void incrementA() {
+		Score score = new Score(3, 5);
+		Score newScore = score.aIncrementBy(1);
+		assertEquals(Score.ab(4, 5), newScore);
+	}
+
+	@Test
+	void incrementB() {
+		Score score = new Score(3, 5);
+		Score newScore = score.bIncrementBy(1);
+		assertEquals(Score.ab(3, 6), newScore);
+	}
 }