[FEAT] : 1차 세미나 과제 선택 구현 - 이모지 포함 글자수 계산 구현

src/main/java/org/sopt/week1/DiaryController.java

@@ -24,7 +24,7 @@ final List<Diary> getList() {
     }
 
     final void post(final String body) {
-        if (body.length() > 30) {
+        if (TextUtils.getLengthOfBody(body) > 30) {
             throw new IllegalArgumentException("30자 이하로 적어주세요");
         }
         diaryService.writeDiary(body);

src/main/java/org/sopt/week1/TextUtils.java

@@ -0,0 +1,24 @@
+package org.sopt.week1;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class TextUtils {
+
+    private static final Pattern graphemePattern = Pattern.compile("\\X");
+    private static final Matcher graphemeMatcher = graphemePattern.matcher("");
+
+    public static int getLengthOfBody(final String body) {
+        if (body == null) {
+            return 0;
+        }
+
+        graphemeMatcher.reset(body);
+
+        int count = 0;
+        while (graphemeMatcher.find()) {
+            count++;
+        }
+        return count;
+    }
+}

src/test/java/TextUtilsTest.java

@@ -0,0 +1,25 @@
+import org.junit.jupiter.api.*;
+import org.sopt.week1.TextUtils;
+
+@DisplayName("일기 글자 수 세기 테스트")
+@DisplayNameGeneration(DisplayNameGenerator.ReplaceUnderscores.class)
+public class TextUtilsTest {
+
+    @Test
+    void 이모지는_한_개의_문자로_인식한다() {
+        //given
+        final String test1 = "😃행복한 하루였어요👍";
+        final String test2 = "🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻";
+        final int expected1 = 11;
+        final int expected2 = 31;
+
+        //when
+        final int actual1 = TextUtils.getLengthOfBody(test1);
+        final int actual2 = TextUtils.getLengthOfBody(test2);
+
+        //then
+        Assertions.assertEquals(actual1, expected1);
+        Assertions.assertEquals(actual2, expected2);
+
+    }
+}