이가연 레이싱카 미션 1단계, 2단계 제출합니다

src/main/java/cholog/RacingCar.java

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+public class RacingCar {
+  private String name;
+
+  public RacingCar(String name) {
+    setName(name);
+  }
+
+  public int moveByRandom(int random){
+    if (random >= 4){
+      return 1; //go
+    }
+    return 0;   //stop
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    if (name == null || name.trim().isEmpty()) {
+      throw new IllegalArgumentException("Racing car name cannot be empty");
+    }
+    this.name = name;
+  }
+}

src/main/java/cholog/RacingContest.java

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+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Random;
+import lombok.Getter;
+
+@Getter
+public class RacingContest {
+  private static final Random random = new Random();
+  private final RacingCar[] RACING_CARS;
+  private final int rounds;
+
+  public RacingContest(RacingCar[] racingCars, int racingRounds) {
+    RACING_CARS = racingCars;
+    rounds = racingRounds;
+  }
+
+  public int[] start(){
+    int[] distances = new int[RACING_CARS.length];
+
+    for (int r = 0; r < rounds; r++) {
+      for (int c = 0; c < RACING_CARS.length; c++) {
+        distances[c] += RACING_CARS[c].moveByRandom(random.nextInt(10));
+      }
+    }
+
+    return distances;
+  }
+
+  public ArrayList<String> ranking(int[] distances){
+    int maxDist = Arrays.stream(distances).max().getAsInt();    // winner decision
+    ArrayList<String> winners = new ArrayList<>();
+
+    for (int i = 0; i < distances.length; i++) {
+      if (distances[i] == maxDist) {
+        winners.add(RACING_CARS[i].getName());
+      }
+    }
+
+    return winners;
+  }
+}

src/test/java/cholog/TestRacingCar.java

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+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+public class TestRacingCar {
+
+  private RacingCar racingCar;
+
+  @BeforeEach
+  void setUp() {
+    racingCar = new RacingCar("myRacingCar");
+  }
+
+  @Test
+  @DisplayName("레이싱카 전진 확인")
+  public void testGo(){
+    //given
+    int random = 9;
+
+    //when
+    int actual = racingCar.moveByRandom(random);
+    int expected = 1;
+
+    //then
+    assertThat(actual).isEqualTo(expected);
+  }
+  @Test
+  @DisplayName("레이싱카 정지 확인")
+  public void testStop(){
+    //given
+    int random = 0;
+
+    //when
+    int actual = racingCar.moveByRandom(random);
+    int expected = 0;
+
+    //then
+    assertThat(actual).isEqualTo(expected);
+  }
+
+  @Test
+  @DisplayName("레이싱카의 이름이 유효하지 않을 시 에러 발생")
+  public void testValidName(){
+    //given
+
+    //when
+
+    //then
+    assertThatThrownBy(() -> {
+      racingCar.setName(null);
+    }).isInstanceOf(IllegalArgumentException.class);
+  }
+}

src/test/java/cholog/TestRacingContest.java

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+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class TestRacingContest {
+  private static int round;
+  private static RacingContest contest;
+  private static final String[] names = new String[]{"neo", "brie", "brown"};
+
+  @BeforeAll
+  public static void setUp() {
+    RacingCar[] participants = new RacingCar[]{
+        new RacingCar(names[0]),
+        new RacingCar(names[1]),
+        new RacingCar(names[2])
+    };
+    round = 10;
+    contest = new RacingContest(participants, round);
+  }
+
+  @Test
+  @DisplayName("경기 결과 모든 차의 주행거리가 0 이상이고 주어진 횟수 round 이하인지 확인")
+  public void testStart() {
+    //given
+    int round = contest.getRounds();
+
+    //when
+    int[] distances = contest.start();
+    int maxDist = Arrays.stream(distances).max().getAsInt();
+    int minDist = Arrays.stream(distances).min().getAsInt();
+
+    //then
+    assertThat(maxDist).isBetween(0, round + 1);
+    assertThat(minDist).isBetween(0, round + 1);
+  }
+  @Test
+  @DisplayName("경기 결과를 바탕으로 우승자를 가려낼 수 있는지 확인")
+  public void testRanking() {
+    //given
+    int[] distances = new int[]{0, round, round};
+    String[] winners = new String[]{names[1], names[2]};
+
+    //when
+    ArrayList<String> actual = contest.ranking(distances);
+    ArrayList<String> expected = new ArrayList<>(Arrays.asList(winners));
+
+    //then
+    assertThat(actual).usingRecursiveComparison().isEqualTo(expected);
+  }
+}