feat: 아이디 중복체크 기능 (#183)

* [#181] feat: 아이디 중복 체크 서비스 로직 작성

* [#181] feat: 아이디 중복 체크 API 작성

src/main/java/com/mallang/auth/application/BasicAuthService.java

@@ -29,4 +29,8 @@ public Long login(String username, String rawPassword) {
         member.login(rawPassword, passwordEncoder);
         return member.getId();
     }
+
+    public boolean checkDuplicatedUsername(String username) {
+        return basicMemberRepository.existsByUsername(username);
+    }
 }

src/main/java/com/mallang/auth/presentation/MemberController.java

@@ -6,6 +6,7 @@
 import com.mallang.auth.application.BasicAuthService;
 import com.mallang.auth.presentation.request.BasicLoginRequest;
 import com.mallang.auth.presentation.request.BasicSignupRequest;
+import com.mallang.auth.presentation.response.CheckDuplicateResponse;
 import com.mallang.auth.presentation.support.Auth;
 import com.mallang.auth.query.MemberQueryService;
 import com.mallang.auth.query.response.MemberResponse;
@@ -15,6 +16,7 @@
 import java.net.URI;
 import lombok.RequiredArgsConstructor;
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.data.repository.query.Param;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -34,6 +36,14 @@ public class MemberController {
     @Value("${auth.session.ttl}")
     private Integer authSessionTTL;
 
+    @GetMapping("/check-duplicate")
+    public ResponseEntity<CheckDuplicateResponse> checkDuplicate(
+            @Param("username") String username
+    ) {
+        boolean duplicated = basicAuthService.checkDuplicatedUsername(username);
+        return ResponseEntity.ok(new CheckDuplicateResponse(duplicated));
+    }
+
     @PostMapping
     public ResponseEntity<Void> signup(
             @Valid @RequestBody BasicSignupRequest request

src/main/java/com/mallang/auth/presentation/response/CheckDuplicateResponse.java

@@ -0,0 +1,6 @@
+package com.mallang.auth.presentation.response;
+
+public record CheckDuplicateResponse(
+        boolean duplicated
+) {
+}

src/test/java/com/mallang/acceptance/auth/MemberAcceptanceSteps.java

@@ -12,6 +12,15 @@
 @SuppressWarnings("NonAsciiCharacters")
 public class MemberAcceptanceSteps {
 
+    public static ExtractableResponse<Response> 아이디_중복_체크_요청(String username) {
+        return given()
+                .queryParam("username", username)
+                .get("/members/check-duplicate")
+                .then()
+                //.log().all()
+                .extract();
+    }
+
     public static ExtractableResponse<Response> 일반_회원가입_요청(BasicSignupRequest request) {
         return given()
                 .body(request)

src/test/java/com/mallang/acceptance/auth/MemberAcceptanceTest.java

@@ -8,6 +8,7 @@
 import static com.mallang.acceptance.AcceptanceSteps.찾을수_없음;
 import static com.mallang.acceptance.auth.AuthAcceptanceSteps.회원가입과_로그인_후_세션_ID_반환;
 import static com.mallang.acceptance.auth.MemberAcceptanceSteps.내_정보_조회_요청;
+import static com.mallang.acceptance.auth.MemberAcceptanceSteps.아이디_중복_체크_요청;
 import static com.mallang.acceptance.auth.MemberAcceptanceSteps.일반_로그인_요청;
 import static com.mallang.acceptance.auth.MemberAcceptanceSteps.일반_회원가입_요청;
 import static com.mallang.acceptance.auth.MemberAcceptanceSteps.회원_정보_조회_결과_데이터;
@@ -17,6 +18,7 @@
 
 import com.mallang.acceptance.AcceptanceTest;
 import com.mallang.auth.presentation.request.BasicSignupRequest;
+import com.mallang.auth.presentation.response.CheckDuplicateResponse;
 import com.mallang.auth.query.response.MemberResponse;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
@@ -39,6 +41,33 @@ class MemberAcceptanceTest extends AcceptanceTest {
             "profile"
     );
 
+    @Nested
+    class 아이디_중복_체크_API {
+
+        @Test
+        void 주어진_아이디가_이미_존재하면_중복됨() {
+            // given
+            일반_회원가입_요청(회원가입_요청);
+
+            // when
+            var 응답 = 아이디_중복_체크_요청(아이디);
+
+            // then
+            CheckDuplicateResponse response = 응답.as(CheckDuplicateResponse.class);
+            assertThat(response.duplicated()).isTrue();
+        }
+
+        @Test
+        void 주어진_아이디가_존재하지_않으면_중복되지_않음() {
+            // when
+            var 응답 = 아이디_중복_체크_요청(아이디);
+
+            // then
+            CheckDuplicateResponse response = 응답.as(CheckDuplicateResponse.class);
+            assertThat(response.duplicated()).isFalse();
+        }
+    }
+
     @Nested
     class 회원가입_API {