diff --git a/build.gradle b/build.gradle
index 8172fb73f..b83664189 100644
--- a/build.gradle
+++ b/build.gradle
@@ -12,6 +12,10 @@ repositories {
 dependencies {
     testImplementation "org.junit.jupiter:junit-jupiter:5.7.2"
     testImplementation "org.assertj:assertj-core:3.19.0"
+    // https://mvnrepository.com/artifact/org.hamcrest/hamcrest
+    testImplementation group: 'org.hamcrest', name: 'hamcrest', version: '2.1'
+    testImplementation "org.junit.jupiter:junit-jupiter-params:5.8.1"
+
 }
 
 test {
diff --git a/src/main/java/baseball/BaseBallMain.java b/src/main/java/baseball/BaseBallMain.java
new file mode 100644
index 000000000..a4444b26c
--- /dev/null
+++ b/src/main/java/baseball/BaseBallMain.java
@@ -0,0 +1,91 @@
+package baseball;
+
+import java.util.Arrays;
+import java.util.Scanner;
+import java.util.stream.Collectors;
+
+public class BaseBallMain {
+
+    public static String[] computerRandomNumbers = new String[3];
+    public static String[] userRandomNumbers = new String[3];
+
+    public static int ballNum = 0;
+    public static int strike = 0;
+    public static boolean isReturnGame = true;
+    public static int isReturnNumber = 0;
+    public static Scanner sc = new Scanner(System.in);
+
+    public static String inputValue() {
+        return sc.next();
+    }
+
+    public static void getComputerRandomNumbers() {
+        for(int i = 0; i < computerRandomNumbers.length;i++) {
+            computerRandomNumbers[i] = String.valueOf((int)(Math.random() * 9) + 1);
+            for(int j = 0; j < i; j++) {
+                if(computerRandomNumbers[i].equals(computerRandomNumbers[j])) {
+                    i--;
+                }
+            }
+        }
+        getComputerRandomNumbersTrans(computerRandomNumbers);
+    }
+
+    public static void getComputerRandomNumbersTrans(String[] computerRandomNumbers) {
+        String resComputerRandomNumbers = Arrays.stream(BaseBallMain.computerRandomNumbers).collect(Collectors.joining());
+        print(resComputerRandomNumbers);
+    }
+
+    public static void characterComparison(String userInputNumbers) {
+        for(int i = 0; i < computerRandomNumbers.length;i++) {
+            if(userInputNumbers.contains(computerRandomNumbers[i])) {
+                indexNumberComparison(userInputNumbers.indexOf(computerRandomNumbers[i]),i);
+            }
+        }
+    }
+
+    public static void indexNumberComparison(int indexNumbers, int i ) {
+        if( indexNumbers == i ) {
+            strike++;
+        } else {
+            ballNum++;
+        }
+    }
+
+    public static void numberBaseBallIsBoolean() {
+        if( strike == 3 ) {
+            System.out.println("3개의 숫자를 모두 맞히셨습니다! 게임 종료");
+            System.out.println("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.");
+            isReturnNumber = Integer.parseInt(inputValue());
+            gameChoiceNumbers(isReturnNumber);
+        }
+    }
+
+    public static void gameChoiceNumbers(int isReturnNumber) {
+        if(isReturnNumber == 2) {
+            isReturnGame = false;
+            return;
+        }
+        getComputerRandomNumbers();
+    }
+
+    public static void print(String resComputerRandomNumbers) {
+        System.out.println("컴퓨터 :" + resComputerRandomNumbers);
+    }
+
+    public static void main(String[] args) {
+        getComputerRandomNumbers();
+
+        String userInputNumber = "";
+
+        while ( isReturnGame ) {
+            System.out.print("숫자를 입력해 주세요 : ");
+            String inputNum = inputValue();
+            characterComparison(inputNum);
+            System.out.println(ballNum + "볼 " + strike + "스트라이크");
+            numberBaseBallIsBoolean();
+            ballNum = 0;
+            strike = 0;
+        }
+    }
+}
diff --git a/src/test/java/study/SetTest.java b/src/test/java/study/SetTest.java
new file mode 100644
index 000000000..061efc35d
--- /dev/null
+++ b/src/test/java/study/SetTest.java
@@ -0,0 +1,78 @@
+package study;
+
+import org.assertj.core.internal.Strings;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/*
+지원을 안해준다.hamcrest
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+*/
+
+/*
+파악 필요
+import static org.hamcrest.MatcherAssert.assertThat;*/
+
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.assertj.core.api.Assertions.*;
+
+
+public class SetTest {
+    private Set<Integer> numbers;
+    // Set은 무엇이며 HashSet은 어떤구조로 이루어져있는가?
+
+    @BeforeEach
+    void setUp() {
+        numbers = new HashSet<>();
+        numbers.add(1);
+        numbers.add(1);
+        numbers.add(2);
+        numbers.add(3);
+    }
+
+    @Test
+    @DisplayName("현재 Set에 담긴 데이터 값이 4개인지")
+    void sizeFour() {
+        assertThat(numbers.size()).isEqualTo(4);
+    }
+
+    @Test
+    @DisplayName("현재 Set에 담긴 데이터 값이 3개인지")
+    void sizeThree() {
+        assertThat(numbers.size()).isEqualTo(3);
+    }
+
+    @Test
+    @DisplayName("값들이 정상적으로 존재하는지 확인")
+    void contains() {
+        assertThat(numbers.contains(1)).isTrue();
+        assertThat(numbers.contains(2)).isTrue();
+        assertThat(numbers.contains(3)).isTrue();
+    }
+
+    // 중복되는 코드들은 생각해서 개발 필요
+    // 둘다 동일한건지 확인 필요 import static org.hamcrest.MatcherAssert.assertThat;
+    @ParameterizedTest
+    @ValueSource(strings = {"", ""})
+    void isBlank_ShouldReturnTrueForNullOrBlankStrings(String input) {
+        assertThat(input).isEqualTo("");
+    }
+
+    // 입력값에 따른 결과값이 달라지는 테스트 구현
+    @ParameterizedTest
+    @CsvSource(value = {"test:test", "tEst:test","Java:java","asb:sss"}, delimiter = ':')
+    void toLowerCase_shouldGenerateTheExpectedLowercaseValue(String input,String expected) {
+        String actualValue = input.toLowerCase();
+        assertThat(expected).isEqualTo(actualValue);
+    }
+
+}
diff --git a/src/test/java/study/StringTest.java b/src/test/java/study/StringTest.java
index 43e47d90b..d9fd11b46 100644
--- a/src/test/java/study/StringTest.java
+++ b/src/test/java/study/StringTest.java
@@ -1,8 +1,9 @@
 package study;
 
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
-import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.*;
 
 public class StringTest {
     @Test
@@ -10,4 +11,61 @@ void replace() {
         String actual = "abc".replace("b", "d");
         assertThat(actual).isEqualTo("adc");
     }
+
+    @Test
+    void test() {
+        String[] actual = {"2"};
+        String s = "123";
+
+        System.out.println(s.indexOf(actual[0]));
+        System.out.println(s.contains(actual[0]));
+    }
+
+    // 요구사항 1
+    @Test
+    void split() {
+        String[] actual = "1,2".split(",");
+        assertThat(actual[0]).isEqualTo("1");
+    }
+
+    @Test
+    void contains() {
+        String[] actual = "1,2".split(",");
+        assertThat(actual).contains(actual[0],actual[1]);
+    }
+
+    @Test
+    void containsExactly() {
+        String[] actual = "1,2".split(",");
+        assertThat(actual).containsExactly(actual[0],actual[1]);
+    }
+
+    // 요구사항 2
+    @Test
+    void substring() {
+        String str = "(1,2)".substring(1,4);
+        assertThat(str).isEqualTo("1,2");
+    }
+
+    // 요구사항 3
+    @Test
+    void charAt() {
+        char oneChar = "123".charAt(5);
+        System.out.println(oneChar);
+    }
+
+    @Test
+    @DisplayName("입력값 범위 밖일 경우 StringIndexOutOfBoundsException 확인")
+    public void StringIndexOutOfBoundsException() {
+        String str = "abc";
+
+        assertThatThrownBy(() -> str.charAt(str.length()))
+                .isInstanceOf(StringIndexOutOfBoundsException.class)
+                .hasMessageContaining("String 범위를 넘어섰습니다.")
+                .hasMessageContaining(String.valueOf(str.length()));
+    }
+
+
+
+
 }
diff --git a/src/test/java/study/baseBallTest/BaseBallTest.java b/src/test/java/study/baseBallTest/BaseBallTest.java
new file mode 100644
index 000000000..ddeabf52b
--- /dev/null
+++ b/src/test/java/study/baseBallTest/BaseBallTest.java
@@ -0,0 +1,5 @@
+package study.baseBallTest;
+
+public class BaseBallTest {
+
+}
diff --git a/src/test/java/study/calculator/Calculator.java b/src/test/java/study/calculator/Calculator.java
new file mode 100644
index 000000000..5932ebb07
--- /dev/null
+++ b/src/test/java/study/calculator/Calculator.java
@@ -0,0 +1,21 @@
+package study.calculator;
+
+public class Calculator {
+
+    public static int add(int a, int b) {
+        return a + b;
+    }
+
+    public static int minus(int a, int b) {
+        return a - b;
+    }
+
+    public static int division(int a, int b) {
+        return a / b;
+    }
+
+    public static int remainder(int a, int b) {
+        return a % b;
+    }
+
+}
diff --git a/src/test/java/study/calculator/CalculatorTest.java b/src/test/java/study/calculator/CalculatorTest.java
new file mode 100644
index 000000000..9b0414f69
--- /dev/null
+++ b/src/test/java/study/calculator/CalculatorTest.java
@@ -0,0 +1,44 @@
+package study.calculator;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class CalculatorTest {
+    Calculator calculator;
+
+    // 생성자 초기화
+    @BeforeEach
+    public void setUp() {
+        calculator = new Calculator();
+    }
+
+    @Test
+    public void 더하기() {
+        assertEquals(5,calculator.add(1,3));
+    }
+
+    @Test
+    public void 빼기() {
+        assertEquals(5,calculator.minus(1,3));
+    }
+
+    @Test
+    public void 나누기() {
+        assertEquals(5,calculator.division(1,3));
+    }
+
+    @Test
+    public void 나머지() {
+        assertEquals(5,calculator.remainder(1,3));
+    }
+
+    // 클래스 null 처리
+    // 이미 한번 선언한 클래스는 계속 쓰레기 영역에 들어가있기때문임. 메모리 낭비
+    @AfterEach
+    public void tearDown() {
+        calculator = null;
+    }
+
+}
diff --git a/src/test/java/study/calculatorNew/AddStrategy.java b/src/test/java/study/calculatorNew/AddStrategy.java
new file mode 100644
index 000000000..18c57d438
--- /dev/null
+++ b/src/test/java/study/calculatorNew/AddStrategy.java
@@ -0,0 +1,8 @@
+package study.calculatorNew;
+
+public class AddStrategy implements CalculatorStrategy{
+    @Override
+    public int calculator(int a, int b) {
+        return a + b;
+    }
+}
diff --git a/src/test/java/study/calculatorNew/CalculatorNew.java b/src/test/java/study/calculatorNew/CalculatorNew.java
new file mode 100644
index 000000000..e15884fff
--- /dev/null
+++ b/src/test/java/study/calculatorNew/CalculatorNew.java
@@ -0,0 +1,17 @@
+package study.calculatorNew;
+
+import java.util.Scanner;
+
+public class CalculatorNew {
+
+    CalculatorStrategy calculatorStrategy;
+
+    CalculatorNew(CalculatorStrategy calculatorStrategy) {
+        this.calculatorStrategy = calculatorStrategy;
+    }
+
+    public int returnResult(int a, int b) {
+        return calculatorStrategy.calculator(a, b);
+    }
+
+}
diff --git a/src/test/java/study/calculatorNew/CalculatorState.java b/src/test/java/study/calculatorNew/CalculatorState.java
new file mode 100644
index 000000000..603005753
--- /dev/null
+++ b/src/test/java/study/calculatorNew/CalculatorState.java
@@ -0,0 +1,4 @@
+package study.calculatorNew;
+
+public enum CalculatorState {
+}
diff --git a/src/test/java/study/calculatorNew/CalculatorStrategy.java b/src/test/java/study/calculatorNew/CalculatorStrategy.java
new file mode 100644
index 000000000..448af7eef
--- /dev/null
+++ b/src/test/java/study/calculatorNew/CalculatorStrategy.java
@@ -0,0 +1,6 @@
+package study.calculatorNew;
+
+// 전략패턴을 이용하여 객체간의 의존성을 낮춰준다.
+public interface CalculatorStrategy {
+    int calculator(int a, int b );
+}
diff --git a/src/test/java/study/calculatorNew/CalculatorTest.java b/src/test/java/study/calculatorNew/CalculatorTest.java
new file mode 100644
index 000000000..7e731ae5f
--- /dev/null
+++ b/src/test/java/study/calculatorNew/CalculatorTest.java
@@ -0,0 +1,27 @@
+package study.calculatorNew;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.*;
+
+public class CalculatorTest {
+
+    CalculatorNew calculatorNew;
+
+    @Test
+    @DisplayName("정상적으로 add의 값이 동일한지 확인")
+    void add() {
+        calculatorNew = new CalculatorNew(new AddStrategy());
+        assertThat(calculatorNew.returnResult(1,3)).isEqualTo(4);
+    }
+
+    @Test
+    @DisplayName("정상적으로 곱의 값이 동일한지 확인")
+    void mut() {
+        calculatorNew = new CalculatorNew(new MultipleStategy());
+        assertThat(calculatorNew.returnResult(1,3)).isEqualTo(4);
+    }
+
+}
diff --git a/src/test/java/study/calculatorNew/MultipleStategy.java b/src/test/java/study/calculatorNew/MultipleStategy.java
new file mode 100644
index 000000000..a750ea8cc
--- /dev/null
+++ b/src/test/java/study/calculatorNew/MultipleStategy.java
@@ -0,0 +1,8 @@
+package study.calculatorNew;
+
+public class MultipleStategy implements CalculatorStrategy{
+    @Override
+    public int calculator(int a , int b) {
+        return a * b;
+    }
+}