diff --git a/README.md b/README.md
index 977f65d2710..42ce4221437 100644
--- a/README.md
+++ b/README.md
@@ -52,3 +52,11 @@
   * 우승자는 차량 이름으로 표시한다.
 * ResultView에서 우승자 목록을 출력한다.
   * 우승자가 여러명일 경우 쉼표(,)로 구분하여 표시한다.
+
+### Step5
+* 아래 3가지 개발 원칙을 적용해본다
+  * 모든 원시값과 문자열을 포장한다
+  * 3개 이상의 인스턴스 변수를 가진 클래스를 쓰지 않는다.
+  * 한 줄에 점을 하나만 찍는다
+  * 일급 콜렉션을 쓴다
+  * 도메인 객체를 테스트가 가능하도록 수정
\ No newline at end of file
diff --git a/src/main/java/race/CarList.java b/src/main/java/race/CarList.java
new file mode 100644
index 00000000000..21aa30726d0
--- /dev/null
+++ b/src/main/java/race/CarList.java
@@ -0,0 +1,42 @@
+package race;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
+public class CarList {
+    private final List<RacingCar> cars;
+
+    public CarList() {
+        this(new ArrayList<>());
+    }
+
+    public CarList(List<RacingCar> cars) {
+        this.cars = cars;
+    }
+
+    public void add(RacingCar car) {
+        cars.add(car);
+    }
+
+    public void moveWithRandom(Random random) {
+        for (RacingCar car : cars) {
+            car.moveWithSeed(random.nextInt());
+        }
+    }
+
+    public List<RacingCar> getList() {
+        return cars;
+    }
+
+    public List<RacingCar> getWinners() {
+        cars.sort(Collections.reverseOrder());
+        RacingCar winner = cars.get(0);
+
+        return cars.stream()
+                .filter(car -> car.compareTo(winner) == 0)
+                .collect(Collectors.toList());
+    }
+}
diff --git a/src/main/java/race/CarName.java b/src/main/java/race/CarName.java
new file mode 100644
index 00000000000..a588b07b601
--- /dev/null
+++ b/src/main/java/race/CarName.java
@@ -0,0 +1,15 @@
+package race;
+
+public class CarName {
+    private final String name;
+
+    public CarName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+
+}
diff --git a/src/main/java/race/DefaultPositionPrinter.java b/src/main/java/race/DefaultPositionPrinter.java
deleted file mode 100644
index d2ca103f7d9..00000000000
--- a/src/main/java/race/DefaultPositionPrinter.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package race;
-
-public class DefaultPositionPrinter implements PositionPrinter {
-    @Override
-    public void printPosition(String carName, int position) {
-        System.out.println("-".repeat(position));
-    }
-}
diff --git a/src/main/java/race/DefaultRandomNumberGenerator.java b/src/main/java/race/DefaultRandomNumberGenerator.java
deleted file mode 100644
index ef44f095354..00000000000
--- a/src/main/java/race/DefaultRandomNumberGenerator.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package race;
-
-import java.util.Random;
-
-public class DefaultRandomNumberGenerator implements RandomNumberGenerator {
-    private final Random random = new Random();
-
-    @Override
-    public int generate() {
-        return random.nextInt(10); // 0~9 사이 랜덤 값 생성
-    }
-}
diff --git a/src/main/java/race/FixedNumberGenerator.java b/src/main/java/race/FixedNumberGenerator.java
deleted file mode 100644
index a4369f3cc90..00000000000
--- a/src/main/java/race/FixedNumberGenerator.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package race;
-
-public class FixedNumberGenerator implements RandomNumberGenerator {
-    private final int fixedValue;
-
-    public FixedNumberGenerator(int fixedValue) {
-        this.fixedValue = fixedValue;
-    }
-
-    @Override
-    public int generate() {
-        return fixedValue;
-    }
-}
diff --git a/src/main/java/race/Position.java b/src/main/java/race/Position.java
new file mode 100644
index 00000000000..8578cab588a
--- /dev/null
+++ b/src/main/java/race/Position.java
@@ -0,0 +1,42 @@
+package race;
+
+import java.util.Objects;
+
+public class Position implements Comparable<Position> {
+    private int value;
+
+    public Position() {
+        this(0);
+    }
+
+    public Position(int value) {
+        this.value = value;
+    }
+
+    public Position move() {
+        this.value++;
+        return this;
+    }
+
+    public int getValue() {
+        return this.value;
+    }
+
+    @Override
+    public int compareTo(Position o) {
+        return Integer.compare(this.value, o.value);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        Position position = (Position) obj;
+        return value == position.value;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(value);
+    }
+}
diff --git a/src/main/java/race/PositionPrinter.java b/src/main/java/race/PositionPrinter.java
deleted file mode 100644
index 724a9e38190..00000000000
--- a/src/main/java/race/PositionPrinter.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package race;
-
-public interface PositionPrinter {
-    void printPosition(String carNumber, int position);
-}
diff --git a/src/main/java/race/RacingCar.java b/src/main/java/race/RacingCar.java
index d8de295bde7..1d2f2d26782 100644
--- a/src/main/java/race/RacingCar.java
+++ b/src/main/java/race/RacingCar.java
@@ -2,20 +2,17 @@
 
 public class RacingCar implements Comparable<RacingCar> {
     private static final int MAX_NAME_LENGTH = 5;
-    private final String name;
-    private int position;
-    private final RandomNumberGenerator randomNumberGenerator;
-    private final PositionPrinter positionPrinter;
+    private static final int MOVE_CRITERIA = 4;
+    private final CarName name;
+    private final Position position;
 
-    private RacingCar(String name, RandomNumberGenerator randomNumberGenerator, PositionPrinter positionPrinter) {
-        this.name = name;
-        this.randomNumberGenerator = randomNumberGenerator;
-        this.positionPrinter = positionPrinter;
+    public RacingCar(String name) {
+        this(name, 0);
     }
 
-    @Override
-    public int compareTo(RacingCar other) {
-        return Integer.compare(this.position, other.position);
+    public RacingCar(String name, int position) {
+        this.name = new CarName(name);
+        this.position = new Position(position);
     }
 
     public static boolean validateName(String carName) {
@@ -23,26 +20,26 @@ public static boolean validateName(String carName) {
     }
 
     private boolean shouldMove(int num) {
-        return num >= 4;
+        return num >= MOVE_CRITERIA;
     }
 
-    public int move() {
-        int randomValue = randomNumberGenerator.generate();
-        if (shouldMove(randomValue)) {
-            position++;
+    public Position moveWithSeed(int seed) {
+        if (shouldMove(seed)) {
+            return this.position.move();
         }
-        return position;
+        return this.position;
     }
 
-    public void printPosition() {
-        positionPrinter.printPosition(name, position);
+    public CarName getName() {
+        return this.name;
     }
 
-    static RacingCar create(String racingName, RandomNumberGenerator randomNumberGenerator, PositionPrinter positionPrinter) {
-        return new RacingCar(racingName, randomNumberGenerator, positionPrinter);
+    public Position getPosition() {
+        return this.position;
     }
 
-    public String getName() {
-        return name;
+    @Override
+    public int compareTo(RacingCar o) {
+        return this.position.compareTo(o.position);
     }
 }
diff --git a/src/main/java/race/RacingCarFactory.java b/src/main/java/race/RacingCarFactory.java
deleted file mode 100644
index 37332e19bc7..00000000000
--- a/src/main/java/race/RacingCarFactory.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package race;
-
-public class RacingCarFactory {
-    private static final RandomNumberGenerator DEFAULT_RANDOM_NUMBER_GENERATOR = new DefaultRandomNumberGenerator();
-    private static final PositionPrinter DEFAULT_POSITION_VIEWER = new DefaultPositionPrinter();
-
-    public static RacingCar create(String carName) {
-        return RacingCar.create(carName, DEFAULT_RANDOM_NUMBER_GENERATOR, DEFAULT_POSITION_VIEWER);
-    }
-
-    public static RacingCar create(String carName, RandomNumberGenerator randomNumberGenerator) {
-        return RacingCar.create(carName, randomNumberGenerator, DEFAULT_POSITION_VIEWER);
-    }
-
-    public static RacingCar create(String carName, PositionPrinter positionPrinter) {
-        return RacingCar.create(carName, DEFAULT_RANDOM_NUMBER_GENERATOR, positionPrinter);
-    }
-
-    public static RacingCar create(String carName, RandomNumberGenerator randomNumberGenerator, PositionPrinter positionPrinter) {
-        return RacingCar.create(carName, randomNumberGenerator, positionPrinter);
-    }
-}
diff --git a/src/main/java/race/RacingTrack.java b/src/main/java/race/RacingTrack.java
index 7422a6d01e8..14c3b65b9de 100644
--- a/src/main/java/race/RacingTrack.java
+++ b/src/main/java/race/RacingTrack.java
@@ -1,18 +1,15 @@
 package race;
 
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
+import java.util.Random;
 
 public class RacingTrack {
-    private final int maxCarCount;
-    private final int maxAttemptCount;
-    private final List<RacingCar> cars;
+    private final TrackCondition trackCondition;
+    private final CarList cars;
 
     public RacingTrack(int maxCarCount, int maxAttemptCount) {
-        this.maxCarCount = maxCarCount;
-        this.maxAttemptCount = maxAttemptCount;
-        this.cars = new ArrayList<>();
+        this.trackCondition = new TrackCondition(maxCarCount, maxAttemptCount);
+        this.cars = new CarList();
     }
 
     public void startRace(String[] carNames, int numOfAttempts) {
@@ -20,44 +17,27 @@ public void startRace(String[] carNames, int numOfAttempts) {
 
         ResultView.printRaceStartMessage();
         for (int i = 0; i < numOfAttempts; i++) {
-            moveAndShowCars();
-            ResultView.printRaceStatus(cars);
-        }
-    }
-
-    // getWinners() 메서드 테스틀 위하여 추가한 생성자
-    public void startRace(List<RacingCar> cars, int numOfAttempts) {
-        this.cars.addAll(cars);
-
-        ResultView.printRaceStartMessage();
-        for (int i = 0; i < numOfAttempts; i++) {
-            moveAndShowCars();
+            cars.moveWithRandom(new Random());
             ResultView.printRaceStatus(cars);
         }
     }
 
     private void setupCars(String[] carNames) {
         for (String name : carNames) {
-            cars.add(RacingCarFactory.create(name, ResultView.createPositionPrinter()));
-        }
-    }
-
-    private void moveAndShowCars() {
-        for (RacingCar car : cars) {
-            car.move();
+            cars.add(new RacingCar(name));
         }
     }
 
     public boolean validateCarCount(int num) {
-        return num >= 1 && num <= this.maxCarCount;
+        return this.trackCondition.validateCarCount(num);
     }
 
     public boolean validateAttemptCount(int num) {
-        return num >= 1 && num <= this.maxAttemptCount;
+        return this.trackCondition.validateAttemptCount(num);
     }
 
     public boolean validateCarNames(String[] names) {
-        if (names.length < 1 || names.length > this.maxCarCount) {
+        if (!this.trackCondition.validateCarCount(names.length)) {
             return false;
         }
         for (String name : names) {
@@ -67,13 +47,6 @@ public boolean validateCarNames(String[] names) {
     }
 
     public List<RacingCar> getWinners() {
-        cars.sort(Collections.reverseOrder());
-        List<RacingCar> winners = new ArrayList<>();
-        winners.add(cars.get(0));
-
-        for (int i = 1; i < cars.size(); i++) {
-            if (cars.get(i).compareTo(cars.get(0)) == 0) winners.add(cars.get(i));
-        }
-        return winners;
+        return this.cars.getWinners();
     }
 }
diff --git a/src/main/java/race/RandomNumberGenerator.java b/src/main/java/race/RandomNumberGenerator.java
deleted file mode 100644
index 06cfbe62e23..00000000000
--- a/src/main/java/race/RandomNumberGenerator.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package race;
-
-public interface RandomNumberGenerator {
-    int generate();
-}
diff --git a/src/main/java/race/ResultView.java b/src/main/java/race/ResultView.java
index a27cc3be9f0..bafbf6cc87d 100644
--- a/src/main/java/race/ResultView.java
+++ b/src/main/java/race/ResultView.java
@@ -3,22 +3,13 @@
 import java.util.List;
 
 public class ResultView {
-    public static PositionPrinter createPositionPrinter() {
-        return new PositionPrinter() {
-            @Override
-            public void printPosition(String carName, int position) {
-                System.out.println(String.format("%-5s", carName) + " : " + "-".repeat(position));
-            }
-        };
-    }
-
     public static void printRaceStartMessage() {
         System.out.println("\n### Racing Start!!! ###\n");
     }
 
-    public static void printRaceStatus(List<RacingCar> cars) {
-        for (RacingCar car : cars) {
-            car.printPosition();
+    public static void printRaceStatus(CarList cars) {
+        for (RacingCar car : cars.getList()) {
+            System.out.println(String.format("%-5s", car.getName().toString()) + " : " + "-".repeat(car.getPosition().getValue()));
         }
         System.out.println();
     }
@@ -26,7 +17,7 @@ public static void printRaceStatus(List<RacingCar> cars) {
     public static void printRaceWinners(List<RacingCar> cars) {
         String[] winners = new String[cars.size()];
         for (RacingCar car : cars) {
-            winners[cars.indexOf(car)] = car.getName();
+            winners[cars.indexOf(car)] = car.getName().toString();
         }
         System.out.println(String.join(", ", winners) + "가 최종 우승했습니다.");
     }
diff --git a/src/main/java/race/TrackCondition.java b/src/main/java/race/TrackCondition.java
new file mode 100644
index 00000000000..1fff6a3a440
--- /dev/null
+++ b/src/main/java/race/TrackCondition.java
@@ -0,0 +1,19 @@
+package race;
+
+public class TrackCondition {
+    private final int maxCarCount;
+    private final int maxAttemptCount;
+
+    public TrackCondition(int maxCarCount, int maxAttemptCount) {
+        this.maxCarCount = maxCarCount;
+        this.maxAttemptCount = maxAttemptCount;
+    }
+
+    public boolean validateCarCount(int num) {
+        return num >= 1 && num <= this.maxCarCount;
+    }
+
+    public boolean validateAttemptCount(int num) {
+        return num >= 1 && num <= this.maxAttemptCount;
+    }
+}
diff --git a/src/test/java/race/DefaultRandomNumberGeneratorTest.java b/src/test/java/race/DefaultRandomNumberGeneratorTest.java
deleted file mode 100644
index 26b4072d18e..00000000000
--- a/src/test/java/race/DefaultRandomNumberGeneratorTest.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package race;
-
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-public class DefaultRandomNumberGeneratorTest {
-    @Test
-    void getRandomNumber() {
-        DefaultRandomNumberGenerator defaultRandomNumberGenerator = new DefaultRandomNumberGenerator();
-        assertThat(defaultRandomNumberGenerator.generate()).isBetween(0, 9);
-    }
-}
diff --git a/src/test/java/race/RacingCarTest.java b/src/test/java/race/RacingCarTest.java
index 6fe139e58f7..b761c069c78 100644
--- a/src/test/java/race/RacingCarTest.java
+++ b/src/test/java/race/RacingCarTest.java
@@ -8,29 +8,16 @@
 public class RacingCarTest {
     @Order(10)
     @Test
-    void move() {
-        RacingCar car = RacingCarFactory.create("1", new FixedNumberGenerator(5));
-        assertThat(car.move()).isEqualTo(1);
-        assertThat(car.move()).isEqualTo(2);
-    }
-
-    @Order(20)
-    @Test
-    void not_move() {
-        RacingCar car = RacingCarFactory.create("1", new FixedNumberGenerator(2));
-        assertThat(car.move()).isEqualTo(0);
-        assertThat(car.move()).isEqualTo(0);
+    void moveWithSeed() {
+        RacingCar car = new RacingCar("1");
+        assertThat(car.moveWithSeed(5)).isEqualTo(new Position(1));
+        assertThat(car.moveWithSeed(2)).isEqualTo(new Position(1));
     }
 
     @Order(30)
     @Test
-    void valid_car_name() {
+    void validate_car_name() {
         assertThat(RacingCar.validateName("test")).isTrue();
-    }
-
-    @Order(40)
-    @Test
-    void invalid_car_name() {
         assertThat(RacingCar.validateName("")).isFalse();
         assertThat(RacingCar.validateName("aaaaaaa")).isFalse();
     }
diff --git a/src/test/java/race/RacingTrackTest.java b/src/test/java/race/RacingTrackTest.java
index 601739b0bab..3abf69c29c0 100644
--- a/src/test/java/race/RacingTrackTest.java
+++ b/src/test/java/race/RacingTrackTest.java
@@ -9,40 +9,25 @@
 
 public class RacingTrackTest {
     @Test
-    void valid_car_count() {
+    void validate_car_count() {
         RacingTrack racingTrack = new RacingTrack(10, 10);
         assertThat(racingTrack.validateCarCount(5)).isTrue();
-    }
-
-    @Test
-    void invalid_car_count() {
-        RacingTrack racingTrack = new RacingTrack(10, 10);
         assertThat(racingTrack.validateCarCount(0)).isFalse();
         assertThat(racingTrack.validateCarCount(15)).isFalse();
     }
 
     @Test
-    void valid_attempt_count() {
+    void validate_attempt_count() {
         RacingTrack racingTrack = new RacingTrack(10, 10);
         assertThat(racingTrack.validateAttemptCount(5)).isTrue();
-    }
-
-    @Test
-    void invalid_attempt_count() {
-        RacingTrack racingTrack = new RacingTrack(10, 10);
         assertThat(racingTrack.validateAttemptCount(0)).isFalse();
         assertThat(racingTrack.validateAttemptCount(15)).isFalse();
     }
 
     @Test
-    void valid_car_names() {
+    void validate_car_names() {
         RacingTrack racingTrack = new RacingTrack(10, 10);
         assertThat(racingTrack.validateCarNames(new String[]{"test1", "test2"})).isTrue();
-    }
-
-    @Test
-    void invalid_car_names() {
-        RacingTrack racingTrack = new RacingTrack(10, 10);
         assertThat(racingTrack.validateCarNames(new String[]{"", "test2"})).isFalse();
         assertThat(racingTrack.validateCarNames(new String[]{"testtesttest", "test2"})).isFalse();
         assertThat(racingTrack.validateCarNames(new String[]{"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11"})).isFalse();
@@ -50,25 +35,21 @@ void invalid_car_names() {
 
     @Test
     void one_winner_test() {
-        RacingCar car1 = RacingCarFactory.create("1", new FixedNumberGenerator(5));
-        RacingCar car2 = RacingCarFactory.create("2", new FixedNumberGenerator(3));
-        List<RacingCar> cars = new ArrayList<>(List.of(car1, car2));
-        RacingTrack racingTrack = new RacingTrack(10, 10);
-        racingTrack.startRace(cars, 5);
-        List<RacingCar> winners = racingTrack.getWinners();
+        RacingCar car1 = new RacingCar("1", 4);
+        RacingCar car2 = new RacingCar("2", 2);
+        CarList cars = new CarList(new ArrayList<>(List.of(car1, car2)));
+        List<RacingCar> winners = cars.getWinners();
         assertThat(winners.size()).isEqualTo(1);
         assertThat(winners.get(0)).isEqualTo(car1);
     }
 
     @Test
     void two_winner_test() {
-        RacingCar car1 = RacingCarFactory.create("1", new FixedNumberGenerator(5));
-        RacingCar car2 = RacingCarFactory.create("2", new FixedNumberGenerator(3));
-        RacingCar car3 = RacingCarFactory.create("3", new FixedNumberGenerator(5));
-        List<RacingCar> cars = new ArrayList<>(List.of(car1, car2, car3));
-        RacingTrack racingTrack = new RacingTrack(10, 10);
-        racingTrack.startRace(cars, 5);
-        List<RacingCar> winners = racingTrack.getWinners();
+        RacingCar car1 = new RacingCar("1", 4);
+        RacingCar car2 = new RacingCar("2", 2);
+        RacingCar car3 = new RacingCar("3", 4);
+        CarList cars = new CarList(new ArrayList<>(List.of(car1, car2, car3)));
+        List<RacingCar> winners = cars.getWinners();
         assertThat(winners.size()).isEqualTo(2);
         assertThat(winners.get(0)).isEqualTo(car1);
         assertThat(winners.get(1)).isEqualTo(car3);