리팩토링: 인터페이스, 일급컬렉션, 테스트코드

build.gradle

@@ -11,9 +11,8 @@ repositories {
 
 dependencies {
     implementation 'org.projectlombok:lombok:1.18.22'
-    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
-    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
-    testImplementation 'org.junit.jupiter:junit-jupiter-params:5.4.2'
+    testImplementation platform('org.junit:junit-bom:5.9.1')
+    testImplementation 'org.junit.jupiter:junit-jupiter'
     implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.0'
 }
 

src/main/java/controller/RacingGameController.java

@@ -1,30 +1,45 @@
 package controller;
 
 import exception.InvalidTryCountException;
-import model.Cars;
+import model.RacingCars;
 import properties.ErrorMessage;
+import service.Movable;
+import service.RandomMoveConstraintsStrategy;
 import view.RacingGameView;
 
 public class RacingGameController {
-
-    private Cars cars;
+    private RacingCars racingCars;
     private int tryCount;
+    private Movable moveStrategy;
 
     public void start() {
-        init();
+        readyForRace();
         race();
-        result();
+        printWinners();
+    }
+
+    private void readyForRace() {
+        initMoveStrategy();
+        askCarNames();
+        askTryCount();
     }
 
-    private void init() {
+    private void initMoveStrategy() {
+        this.moveStrategy = new RandomMoveConstraintsStrategy();
+    }
+
+    private void askCarNames() {
         RacingGameView.askCarNames();
-        initCars(RacingGameView.getConsoleInput());
+        initRacingCars(RacingGameView.getConsoleInput());
+    }
+
+    private void askTryCount() {
         RacingGameView.askTryCount();
         initTryCount(RacingGameView.getConsoleInput());
     }
 
-    private void initCars(final String carNames) {
-        cars = new Cars(carNames);
+    private void initRacingCars(final String carNames) {
+        this.racingCars = new RacingCars(carNames);
     }
 
     private void initTryCount(final String tryCount) {
@@ -46,13 +61,13 @@ private int parsedTryCount(String tryCount) {
     private void race() {
         int playCount = 0;
         while (playCount != tryCount) {
-            cars.move();
-            cars.moveResult();
+            racingCars.move(moveStrategy);
+            racingCars.moveResult();
             playCount++;
         }
     }
 
-    private void result() {
-        cars.pickWinners();
+    private void printWinners() {
+        racingCars.printWinners();
     }
 }

src/main/java/exception/InvalidPositionException.java

@@ -0,0 +1,7 @@
+package exception;
+
+public class InvalidPositionException extends RacingGameException {
+    public InvalidPositionException(String message) {
+        super(message);
+    }
+}

src/main/java/model/Car.java

@@ -1,11 +1,12 @@
 package model;
 
+import service.Movable;
 import view.RacingGameView;
 
 public class Car {
 
     private final CarName name;
-    private final Position position;
+    private Position position;
 
     public Car(String name) {
         this(name, 0);
@@ -16,26 +17,26 @@ public Car(String name, int position) {
         this.position = new Position(position);
     }
 
-    public void move() {
-        if (!position.canMove())
+    public void move(Movable moveStrategy) {
+        if (!moveStrategy.canMove())
             return;
 
-        position.increasePosition();
+        this.position = this.position.increasePosition();
     }
 
     public void printCurrPosition() {
         RacingGameView.printText(
-                name.getName() + " : " + position.indicateCharacterByPosition()
+                name.getName() + " : " + position.getPosition()
         );
     }
 
     public int getCurrentPosition() {
-        return position.getPosition();
+        return position.getPosition().length();
     }
 
     public String getNameIfWin(int winnerPosition) {
-        if (position.getPosition() == winnerPosition)
-            return name.getName() + ", ";
+        if (position.getPosition().length() == winnerPosition)
+            return name.getName();
 
         return "";
     }

src/main/java/model/Cars.java

@@ -2,17 +2,24 @@
 
 import exception.InvalidCarNameException;
 import properties.ErrorMessage;
+import service.Movable;
 import view.RacingGameView;
 
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 public class Cars {
     private final List<Car> cars;
 
     private static final String CAR_NAME_DELIMITER = ",";
 
+    public Cars(List<Car> cars) {
+        this.cars = cars;
+    }
+
     public Cars(String carNames) {
         this.cars = makeCars(carNames);
     }
@@ -22,8 +29,8 @@ public List<Car> makeCars(String carNames) {
         return parsedCarNames(carNames).stream().map(Car::new).toList();
     }
 
-    public void move() {
-        cars.forEach(Car::move);
+    public void move(Movable moveStrategy) {
+        cars.forEach(car -> car.move(moveStrategy));
     }
 
     public void moveResult() {
@@ -32,12 +39,19 @@ public void moveResult() {
         RacingGameView.printLine();
     }
 
-    public void pickWinners() {
-        int winnerPosition = cars.stream().mapToInt(Car::getCurrentPosition).max().getAsInt();
+    public int getWinnerPosition() {
+        return cars.stream().mapToInt(Car::getCurrentPosition).max().getAsInt();
+    }
+
+    public List<String> findWinnerNamesByPosition(int winnerPosition) {
         StringBuilder result = new StringBuilder();
-        cars.forEach(car -> result.append(car.getNameIfWin(winnerPosition)));
-        String winners = result.substring(0, result.length() - 2);
-        RacingGameView.printText(winners + "가 최종 우승했습니다.");
+        cars.forEach(car ->
+                result.append(car.getNameIfWin(winnerPosition)).append(",")
+        );
+
+        return Stream.of(result.toString().split(","))
+                .filter(winner -> !winner.isBlank())
+                .collect(Collectors.toList());
     }
 
     private void validNames(String carNames) {

src/main/java/model/Position.java

@@ -1,34 +1,45 @@
 package model;
 
-public class Position {
+import exception.InvalidPositionException;
+import properties.ErrorMessage;
+
+import java.util.Objects;
 
-    private int position;
+public class Position {
 
-    private static final int MOVE_CONDITION = 4;
+    private final int position;
 
     private static final String DISPLAY_CHARACTER = "-";
 
-    public Position(int position) {
-        this.position = position;
+    public Position() {
+        this(0);
     }
 
-    public int getPosition() {
-        return position;
+    public Position(int position) {
+        if (position < 0)
+            throw new InvalidPositionException(ErrorMessage.Position.NOT_POSITIVE_NUMBER);
+
+        this.position = position;
     }
 
-    public void increasePosition() {
-        position++;
+    public Position increasePosition() {
+        return new Position(position + 1);
     }
 
-    public boolean canMove() {
-        return createRandomNumber() >= MOVE_CONDITION;
+    public String getPosition() {
+        return DISPLAY_CHARACTER.repeat(Math.max(0, position));
     }
 
-    public int createRandomNumber() {
-        return (int) (Math.random() * 10);
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Position position1 = (Position) o;
+        return position == position1.position;
     }
 
-    public String indicateCharacterByPosition() {
-        return DISPLAY_CHARACTER.repeat(Math.max(0, position));
+    @Override
+    public int hashCode() {
+        return Objects.hash(position);
     }
 }

src/main/java/model/RacingCars.java

@@ -0,0 +1,34 @@
+package model;
+
+import org.apache.commons.lang3.StringUtils;
+import service.Movable;
+import view.RacingGameView;
+
+import java.util.List;
+
+public class RacingCars {
+
+    private final Cars cars;
+
+    public RacingCars(String carNames) {
+        this.cars = new Cars(carNames);
+    }
+
+    public void move(Movable moveStrategy) {
+        cars.move(moveStrategy);
+    }
+
+    public void moveResult() {
+        cars.moveResult();
+    }
+
+    public void printWinners() {
+        RacingGameView.printText(findWinnerNames() + "가 최종 우승했습니다.");
+    }
+
+    private String findWinnerNames() {
+        List<String> winners = cars.findWinnerNamesByPosition(cars.getWinnerPosition());
+        return StringUtils.join(winners, ", ");
+    }
+
+}

src/main/java/properties/ErrorMessage.java

@@ -14,4 +14,8 @@ public static class CarName {
     public static class TryCount {
         public static final String NOT_POSITIVE_NUMBER = "[ERROR] 시도 횟수 입력값은 1 이상의 정수여야만 합니다.";
     }
+
+    public static class Position {
+        public static final String NOT_POSITIVE_NUMBER = "[ERROR] 위치 값은 음수일 수 없습니다.";
+    }
 }

src/main/java/service/Movable.java

@@ -0,0 +1,6 @@
+package service;
+
+@FunctionalInterface
+public interface Movable {
+    boolean canMove();
+}

src/main/java/service/RandomMoveConstraintsStrategy.java

@@ -0,0 +1,11 @@
+package service;
+
+public class RandomMoveConstraintsStrategy implements Movable {
+
+    private static final int CONSTRAINTS = 4;
+
+    @Override
+    public boolean canMove() {
+        return (int) (Math.random() * 10) >= CONSTRAINTS;
+    }
+}

src/test/java/model/CarNameTest.java

@@ -0,0 +1,21 @@
+package model;
+
+import exception.InvalidCarNameException;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import properties.ErrorMessage;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class CarNameTest {
+
+    @ParameterizedTest
+    @ValueSource(strings = {"123456"})
+    @DisplayName("잘못된 자동차 이름 에러 테스트")
+    void test(String parameter) {
+        InvalidCarNameException invalidCarNameException = assertThrows(InvalidCarNameException.class, () -> new CarName(parameter));
+        assertEquals(ErrorMessage.CarName.NOT_EXCEED_CAR_NAME_LENGTH, invalidCarNameException.getMessage());
+    }
+}

src/test/java/model/CarTest.java

@@ -0,0 +1,27 @@
+package model;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class CarTest {
+
+    @Test
+    @DisplayName("move전략의 움직임 여부가 true면 위치값이 1 증가한다.")
+    void test() {
+        Car car = new Car("seung");
+        car.move(() -> true);
+
+        assertEquals(1, car.getCurrentPosition());
+    }
+
+    @Test
+    @DisplayName("move전략의 움직임 여부가 false면 움직이지 않는다.")
+    void test2() {
+        Car car = new Car("seung");
+        car.move(() -> false);
+
+        assertEquals(0, car.getCurrentPosition());
+    }
+}