refactor: 기물 위치 변위 계산 메소드 네이밍 수정

src/main/java/model/board/Position.java

@@ -17,7 +17,7 @@ public record Position(int row, int col) {
         }
     }
 
-    public Displacement minus(Position other) {
+    public Displacement toDisplacement(Position other) {
         return new Displacement(calculateRowDiff(other), calculateColDiff(other));
     }
 

src/main/java/model/movement/LinearStrategy.java

@@ -7,7 +7,7 @@
 public class LinearStrategy implements MoveStrategy {
 
     private static Direction resolveCardinal(Position start, Position end) {
-        Displacement displacement = end.minus(start);
+        Displacement displacement = end.toDisplacement(start);
         return displacement.extractCardinal();
     }
 

src/main/java/model/movement/OneStepStrategy.java

@@ -7,7 +7,7 @@ public class OneStepStrategy implements MoveStrategy {
 
     @Override
     public List<Position> extractPath(Position start, Position end) {
-        Displacement displacement = end.minus(start);
+        Displacement displacement = end.toDisplacement(start);
         Direction cardinal = displacement.extractCardinal();
 
         Position step = cardinal.move(start);

src/main/java/model/movement/SteppingStrategy.java

@@ -7,7 +7,7 @@ public class SteppingStrategy implements MoveStrategy {
 
     @Override
     public List<Position> extractPath(Position start, Position end) {
-        Displacement displacement = end.minus(start);
+        Displacement displacement = end.toDisplacement(start);
         Direction cardinal = displacement.extractCardinal();
         Direction diagonal = displacement.extractDiagonal();
 

src/main/java/model/piece/Cannon.java

@@ -35,7 +35,7 @@ public void validateTarget(Piece otherPiece) {
 
     @Override
     protected void validateMove(Position current, Position next) {
-        Displacement displacement = next.minus(current);
+        Displacement displacement = next.toDisplacement(current);
         if (displacement.isNotStraight()) {
             throw new IllegalArgumentException("포가 이동할 수 없는 위치입니다.");
         }

src/main/java/model/piece/Chariot.java

@@ -12,7 +12,7 @@ public Chariot(Team team) {
 
     @Override
     protected void validateMove(Position current, Position next) {
-        Displacement displacement = next.minus(current);
+        Displacement displacement = next.toDisplacement(current);
         if (displacement.isNotStraight()) {
             throw new IllegalArgumentException("차가 이동할 수 없는 위치입니다.");
         }

src/main/java/model/piece/Elephant.java

@@ -15,7 +15,7 @@ public Elephant(Team team) {
 
     @Override
     protected void validateMove(Position current, Position next) {
-        Displacement displacement = next.minus(current);
+        Displacement displacement = next.toDisplacement(current);
         if (displacement.isNotStepCombination(ELEPHANT_LONG_STEP, ELEPHANT_SHORT_STEP)) {
             throw new IllegalArgumentException("상이 이동할 수 없는 위치입니다.");
         }

src/main/java/model/piece/Horse.java

@@ -15,7 +15,7 @@ public Horse(Team team) {
 
     @Override
     protected void validateMove(Position current, Position next) {
-        Displacement displacement = next.minus(current);
+        Displacement displacement = next.toDisplacement(current);
         if (displacement.isNotStepCombination(HORSE_LONG_STEP, HORSE_SHORT_STEP)) {
             throw new IllegalArgumentException("마가 이동할 수 없는 위치입니다.");
         }

src/main/java/model/piece/Soldier.java

@@ -6,27 +6,25 @@
 
 public class Soldier extends Piece {
 
-    private static final int SOLDIER_FORWARD_STEP = 1;
+    private final int forwardDirection;
 
     public Soldier(Team team) {
         super(team, PieceType.SOLDIER);
+        this.forwardDirection = resolveForwardDirection(team);
     }
 
-    @Override
-    protected void validateMove(Position current, Position next) {
-        Displacement displacement = next.minus(current);
-        int forwardCount = resolveForwardCount();
-
-        if (!(displacement.isForwardBy(forwardCount) || displacement.isSideOneStep())) {
-            throw new IllegalArgumentException("졸이 이동할 수 없는 위치입니다.");
+    private static int resolveForwardDirection(Team team) {
+        if (team.isHan()) {
+            return 1;
         }
+        return -1;
     }
 
-    private int resolveForwardCount() {
-        if (isCho()) {
-            return -SOLDIER_FORWARD_STEP;
+    @Override
+    protected void validateMove(Position current, Position next) {
+        Displacement displacement = next.toDisplacement(current);
+        if (!(displacement.isForwardBy(forwardDirection) || displacement.isSideOneStep())) {
+            throw new IllegalArgumentException("졸이 이동할 수 없는 위치입니다.");
         }
-        return SOLDIER_FORWARD_STEP;
     }
-
 }

src/test/java/model/board/PositionTest.java

@@ -43,7 +43,7 @@ class PositionTest {
         Position end = new Position(3, 7);
 
         // when
-        Displacement result = end.minus(start);
+        Displacement result = end.toDisplacement(start);
 
         // then
         assertThat(result.rowDiff()).isEqualTo(-2);