Maintenance: SimpleKoreanEmbeddingService - Improve dependency injection and add comprehensive tests (#100)

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: Claude <[email protected]>

Author: 3 people

src/main/java/spring/memewikibe/infrastructure/ai/SimpleKoreanEmbeddingService.java

@@ -1,19 +1,41 @@
 package spring.memewikibe.infrastructure.ai;
 
 import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Service;
 
 /**
- * Default stub implementation for KoreanEmbeddingService.
- * For now, it delegates to the existing EmbeddingService implementation (Vertex/Default).
- * Later, replace this with a NAVER embedding client and keep the interface stable.
+ * Adapter implementation for KoreanEmbeddingService that delegates to the primary EmbeddingService.
+ *
+ * <p>This implementation serves as a transitional adapter while Korean-specific embedding
+ * capabilities are being developed. It currently delegates to VertexAiEmbeddingService
+ * (or DefaultEmbeddingService as fallback) for generating embeddings.
+ *
+ * <p><strong>Future Enhancement:</strong> This implementation will be replaced with a
+ * NAVER AI Studio embedding client optimized for Korean text. The KoreanEmbeddingService
+ * interface will remain stable to avoid impacting dependent code.
+ *
+ * @see KoreanEmbeddingService
+ * @see EmbeddingService
  */
 @Service
 @RequiredArgsConstructor
 public class SimpleKoreanEmbeddingService implements KoreanEmbeddingService {
 
-    private final EmbeddingService delegate; // existing embedding provider bean
+    /**
+     * The primary embedding service to delegate to.
+     * Explicitly qualified to avoid ambiguity with multiple EmbeddingService implementations.
+     */
+    @Qualifier("vertexAiEmbeddingService")
+    private final EmbeddingService delegate;
 
+    /**
+     * Generates an embedding vector for the given Korean text.
+     *
+     * @param text the input text to embed (may be null or blank)
+     * @return a float array representing the embedding vector
+     * @throws IllegalArgumentException if text processing fails
+     */
     @Override
     public float[] embed(String text) {
         return delegate.embed(text);

src/test/java/spring/memewikibe/infrastructure/ai/SimpleKoreanEmbeddingServiceTest.java

@@ -0,0 +1,143 @@
+package spring.memewikibe.infrastructure.ai;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import spring.memewikibe.annotation.UnitTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@UnitTest
+@ExtendWith(MockitoExtension.class)
+@DisplayName("SimpleKoreanEmbeddingService 단위 테스트")
+class SimpleKoreanEmbeddingServiceTest {
+
+    @Mock
+    private EmbeddingService mockEmbeddingService;
+
+    private SimpleKoreanEmbeddingService sut;
+
+    @BeforeEach
+    void setUp() {
+        sut = new SimpleKoreanEmbeddingService(mockEmbeddingService);
+    }
+
+    @Test
+    @DisplayName("embed: 정상적인 한글 텍스트를 임베딩 벡터로 변환")
+    void embed_succeeds_withValidKoreanText() {
+        // given
+        String koreanText = "안녕하세요 밈 위키입니다";
+        float[] expectedEmbedding = new float[]{0.1f, 0.2f, 0.3f};
+        when(mockEmbeddingService.embed(koreanText)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(koreanText);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        verify(mockEmbeddingService).embed(koreanText);
+    }
+
+    @Test
+    @DisplayName("embed: null 텍스트를 delegate에 전달")
+    void embed_delegatesNullText_toUnderlyingService() {
+        // given
+        String nullText = null;
+        float[] expectedEmbedding = new float[]{0.0f, 0.0f, 0.0f};
+        when(mockEmbeddingService.embed(nullText)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(nullText);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        verify(mockEmbeddingService).embed(nullText);
+    }
+
+    @Test
+    @DisplayName("embed: 빈 문자열을 delegate에 전달")
+    void embed_delegatesEmptyString_toUnderlyingService() {
+        // given
+        String emptyText = "";
+        float[] expectedEmbedding = new float[]{0.0f, 0.0f, 0.0f};
+        when(mockEmbeddingService.embed(emptyText)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(emptyText);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        verify(mockEmbeddingService).embed(emptyText);
+    }
+
+    @Test
+    @DisplayName("embed: 공백만 있는 문자열을 delegate에 전달")
+    void embed_delegatesBlankString_toUnderlyingService() {
+        // given
+        String blankText = "   ";
+        float[] expectedEmbedding = new float[]{0.0f, 0.0f, 0.0f};
+        when(mockEmbeddingService.embed(blankText)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(blankText);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        verify(mockEmbeddingService).embed(blankText);
+    }
+
+    @Test
+    @DisplayName("embed: 긴 한글 텍스트를 임베딩 벡터로 변환")
+    void embed_succeeds_withLongKoreanText() {
+        // given
+        String longText = "밈(Meme)은 문화적 정보나 아이디어가 사람들 사이에서 전파되는 것을 설명하는 개념입니다. " +
+            "인터넷 밈은 일반적으로 이미지, 동영상, 해시태그 등의 형태로 소셜 미디어를 통해 빠르게 확산됩니다.";
+        float[] expectedEmbedding = new float[1536]; // typical embedding dimension
+        when(mockEmbeddingService.embed(longText)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(longText);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        assertThat(result.length).isEqualTo(1536);
+        verify(mockEmbeddingService).embed(longText);
+    }
+
+    @Test
+    @DisplayName("embed: 혼합된 한글/영어 텍스트를 처리")
+    void embed_succeeds_withMixedKoreanEnglishText() {
+        // given
+        String mixedText = "Meme은 밈입니다 #trending #인기밈";
+        float[] expectedEmbedding = new float[]{0.5f, 0.6f, 0.7f};
+        when(mockEmbeddingService.embed(mixedText)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(mixedText);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        verify(mockEmbeddingService).embed(mixedText);
+    }
+
+    @Test
+    @DisplayName("embed: 특수문자가 포함된 텍스트를 처리")
+    void embed_succeeds_withSpecialCharacters() {
+        // given
+        String textWithSpecialChars = "안녕하세요! 😀 #밈 @사용자 https://example.com";
+        float[] expectedEmbedding = new float[]{0.8f, 0.9f, 1.0f};
+        when(mockEmbeddingService.embed(textWithSpecialChars)).thenReturn(expectedEmbedding);
+
+        // when
+        float[] result = sut.embed(textWithSpecialChars);
+
+        // then
+        assertThat(result).isEqualTo(expectedEmbedding);
+        verify(mockEmbeddingService).embed(textWithSpecialChars);
+    }
+}