테스트 코드 (JUnit)

import org.junit.jupiter.api.*;
import org.mockito.*;
import static org.mockito.Mockito.*;
import static org.assertj.core.api.Assertions.*;

@ExtendWith(MockitoExtension.class)
class UserServiceTest {

    @Mock
    private UserRepository userRepository;

    @InjectMocks
    private UserService userService;

    @Test
    @DisplayName("이메일로 사용자 조회 성공")
    void findByEmail_success() {
        // Given
        User expected = new User(1L, "홍길동", "hong@test.com");
        when(userRepository.findByEmail("hong@test.com"))
            .thenReturn(Optional.of(expected));

        // When
        User result = userService.findByEmail("hong@test.com");

        // Then
        assertThat(result.getName()).isEqualTo("홍길동");
        assertThat(result.getEmail()).isEqualTo("hong@test.com");
        verify(userRepository, times(1)).findByEmail("hong@test.com");
    }

    @Test
    @DisplayName("존재하지 않는 이메일 예외 발생")
    void findByEmail_notFound() {
        when(userRepository.findByEmail(anyString())).thenReturn(Optional.empty());

        assertThatThrownBy(() -> userService.findByEmail("none@test.com"))
            .isInstanceOf(ResourceNotFoundException.class);
    }
}