step3

src/main/java/Car.java

@@ -0,0 +1,30 @@
+public class Car {
+    private static final int STANDARD_VALUE = 4;
+    private int position;
+
+    public Car(int position) {
+        this.position = position;
+    }
+
+    public Car() {
+        this(0);
+    }
+
+    public Car(Car car) {
+        this.position = car.position;
+    }
+
+    public void moveBy(int value) {
+        if (value > STANDARD_VALUE) {
+            this.position++;
+        }
+    }
+
+    public boolean isPosition(int value) {
+        return this.position == value;
+    }
+
+    public int getPosition() {
+        return this.position;
+    }
+}

src/main/java/Cars.java

@@ -0,0 +1,23 @@
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class Cars {
+    private final List<Car> cars;
+
+    public Cars(int carNum) {
+        this.cars = Stream.generate(Car::new).limit(carNum).collect(Collectors.toList());
+    }
+
+    public Cars(Cars cars) {
+        this.cars = cars.cars.stream().map(Car::new).collect(Collectors.toList());
+    }
+
+    public void move() {
+        this.cars.forEach(car -> car.moveBy(RandomNumberUtil.getRandomNumberFromZeroToNine()));
+    }
+
+    public List<Car> getCars() {
+        return this.cars;
+    }
+}

src/main/java/CarsSnapShots.java

@@ -0,0 +1,18 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class CarsSnapShots {
+    private final List<Cars> carsSnapShots;
+
+    public CarsSnapShots() {
+        this.carsSnapShots = new ArrayList<>();
+    }
+
+    public void add(Cars cars) {
+        this.carsSnapShots.add(new Cars(cars));
+    }
+
+    public List<Cars> getCars() {
+        return this.carsSnapShots;
+    }
+}

src/main/java/InputView.java

@@ -0,0 +1,18 @@
+import java.util.Scanner;
+
+public final class InputView {
+
+    private InputView() {}
+
+    public static int inputCarNum() {
+        final Scanner scanner = new Scanner(System.in);
+        System.out.println("자동차 대수는 몇 대 인가요?");
+        return scanner.nextInt();
+    }
+
+    public static int inputTryNum() {
+        final Scanner scanner = new Scanner(System.in);
+        System.out.println("시도할 회수는 몇 회 인가요?");
+        return scanner.nextInt();
+    }
+}

src/main/java/Main.java

@@ -0,0 +1,13 @@
+public class Main {
+    public static void main(String[] args) {
+        final int carNum = InputView.inputCarNum();
+        final int tryNum = InputView.inputTryNum();
+
+        final RacingManager racingManager = new RacingManager(carNum, tryNum);
+
+        racingManager.play();
+
+        ResultView.printTitle();
+        ResultView.printResult(racingManager.getCarsSnapShots());
+    }
+}

src/main/java/RacingManager.java

@@ -0,0 +1,25 @@
+public class RacingManager {
+    private final Cars cars;
+    private final CarsSnapShots carsSnapShots;
+    private final int tryNum;
+
+    public RacingManager(int carNum, int tryNum) {
+        if (carNum <= 0 || tryNum <= 0) {
+            throw new IllegalArgumentException("자동차 대수와 시도 횟수는 0보다 커야 합니다.");
+        }
+        this.tryNum = tryNum;
+        this.cars = new Cars(carNum);
+        carsSnapShots = new CarsSnapShots();
+    }
+
+    public void play() {
+        for (int i = 0; i < tryNum; i++) {
+            this.cars.move();
+            carsSnapShots.add(this.cars);
+        }
+    }
+
+    public CarsSnapShots getCarsSnapShots() {
+        return this.carsSnapShots;
+    }
+}

src/main/java/RandomNumberUtil.java

@@ -0,0 +1,7 @@
+public final class RandomNumberUtil {
+    private RandomNumberUtil() {}
+
+    public static int getRandomNumberFromZeroToNine() {
+        return (int) (Math.random() * 10);
+    }
+}

src/main/java/ResultView.java

@@ -0,0 +1,22 @@
+public final class ResultView {
+
+    private ResultView() {}
+
+    public static void printResult(final CarsSnapShots carsSnapShots) {
+        carsSnapShots.getCars().forEach(cars -> {
+            cars.getCars().forEach(car -> {
+                printCarPosition(car.getPosition());
+                System.out.println();
+            });
+            System.out.println();
+        });
+    }
+
+    public static void printTitle() {
+        System.out.println("실행 결과");
+    }
+
+    private static void printCarPosition(int position) {
+        System.out.print("-".repeat(position));
+    }
+}

src/test/java/CarTest.java

@@ -0,0 +1,22 @@
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class CarTest {
+    @Test
+    @DisplayName("기준값 보다 크면 1칸 이동한다")
+    void moveBy_go() {
+        final Car car = new Car();
+        car.moveBy(5);
+        assertThat(car.isPosition(1)).isTrue();
+    }
+
+    @Test
+    @DisplayName("기준값 보다 작으면 이동하지 않는다")
+    void moveBy_wait() {
+        final Car car = new Car();
+        car.moveBy(4);
+        assertThat(car.isPosition(0)).isTrue();
+    }
+}

src/test/java/RacingManagerTest.java

@@ -0,0 +1,23 @@
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class RacingManagerTest {
+
+    @Test
+    @DisplayName("자동차 개수와 시도 횟수가 0보다 작을 때 예외를 던진다.")
+    void car() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            new RacingManager(0, 5);
+        });
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            new RacingManager(3, 0);
+        });
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            new RacingManager(0, 0);
+        });
+    }
+}

src/test/java/RandomNumberUtilTest.java

@@ -0,0 +1,13 @@
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class RandomNumberUtilTest {
+
+    @Test
+    @DisplayName("0부터 9까지의 랜덤 숫자를 반환한다.")
+    void getRandomNumberFromZeroToNine() {
+        assertThat(RandomNumberUtil.getRandomNumberFromZeroToNine()).isBetween(0, 9);
+    }
+}