diff --git a/src/test/java/com/snsIntegrationFeedService/user/service/UserServiceTest.java b/src/test/java/com/snsIntegrationFeedService/user/service/UserServiceTest.java
new file mode 100644
index 0000000..4168b91
--- /dev/null
+++ b/src/test/java/com/snsIntegrationFeedService/user/service/UserServiceTest.java
@@ -0,0 +1,90 @@
+package com.snsIntegrationFeedService.user.service;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.util.Optional;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+import com.snsIntegrationFeedService.certificateCode.entity.CertificateCode;
+import com.snsIntegrationFeedService.certificateCode.repository.CertificateCodeRepository;
+import com.snsIntegrationFeedService.common.error.CustomErrorCode;
+import com.snsIntegrationFeedService.common.exception.CustomException;
+import com.snsIntegrationFeedService.user.dto.SignupRequestDto;
+import com.snsIntegrationFeedService.user.entity.User;
+import com.snsIntegrationFeedService.user.repository.UserRepository;
+
+@ExtendWith(MockitoExtension.class)
+class UserServiceTest {
+
+	@InjectMocks
+	private UserService userService;
+
+	@Mock
+	private UserRepository userRepository;
+
+	@Mock
+	private CertificateCodeRepository certificateCodeRepository;
+
+	@Mock
+	private PasswordEncoder passwordEncoder;
+
+	@Mock
+	private PasswordValidation passwordValidation;
+
+	@Test
+	void 회원가입_test() throws Exception {
+		// given
+		SignupRequestDto signupRequestDto = SignupRequestDto.builder()
+			.account("test")
+			.email("test@test.com")
+			.password("test123")
+			.build();
+
+		// stub 1
+		when(userRepository.findByAccount(any())).thenReturn(Optional.empty());
+
+		// stub 2
+		when(passwordEncoder.encode(any())).thenReturn("encodedPassword");
+
+		// when
+		userService.signup(signupRequestDto);
+
+		// then
+		verify(userRepository).save(any(User.class));
+		verify(certificateCodeRepository).save(any(CertificateCode.class));
+	}
+
+	@Test
+	void 회원가입_실패_중복_test() throws Exception {
+		// given
+		SignupRequestDto signupRequestDto = SignupRequestDto.builder()
+			.account("test")
+			.email("test@test.com")
+			.password("test123")
+			.build();
+
+		User user = User.builder()
+			.account("test")
+			.email("test@test.com")
+			.password("test123")
+			.build();
+
+		// stub 1
+		when(userRepository.findByAccount(any())).thenReturn(Optional.of(user));
+
+		// when
+		CustomException exception = assertThrows(CustomException.class, () -> {
+			userService.signup(signupRequestDto);
+		});
+
+		// then
+		assertEquals(CustomErrorCode.USER_ALREADY_EXIST, exception.getErrorCode());
+	}
+}
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