diff --git a/놀이터(예제 코드 작성)/learn-with-making-clean-architecture/src/test/kotlin/com/banjjoknim/cleanarchitecture/user/domain/NicknameTest.kt b/놀이터(예제 코드 작성)/learn-with-making-clean-architecture/src/test/kotlin/com/banjjoknim/cleanarchitecture/user/domain/NicknameTest.kt
new file mode 100644
index 0000000..d1b4a85
--- /dev/null
+++ b/놀이터(예제 코드 작성)/learn-with-making-clean-architecture/src/test/kotlin/com/banjjoknim/cleanarchitecture/user/domain/NicknameTest.kt	
@@ -0,0 +1,24 @@
+package com.banjjoknim.cleanarchitecture.user.domain
+
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertDoesNotThrow
+import org.junit.jupiter.api.assertThrows
+
+class NicknameTest {
+
+    @DisplayName("닉네임 생성 테스트")
+    @Nested
+    inner class ChangeNicknameTestCases {
+        @Test
+        fun `10글자 이내이면 닉네임을 생성할 수 있다`() {
+            assertDoesNotThrow { Nickname("banjjoknim") }
+        }
+
+        @Test
+        fun `10글자가 넘으면 닉네임을 생성할 경우 예외가 발생한다`() {
+            assertThrows<IllegalArgumentException> { Nickname("i'm banjjoknim") }
+        }
+    }
+}
diff --git a/놀이터(예제 코드 작성)/learn-with-making-clean-architecture/src/test/kotlin/com/banjjoknim/cleanarchitecture/user/domain/UserTest.kt b/놀이터(예제 코드 작성)/learn-with-making-clean-architecture/src/test/kotlin/com/banjjoknim/cleanarchitecture/user/domain/UserTest.kt
new file mode 100644
index 0000000..c96ac86
--- /dev/null
+++ b/놀이터(예제 코드 작성)/learn-with-making-clean-architecture/src/test/kotlin/com/banjjoknim/cleanarchitecture/user/domain/UserTest.kt	
@@ -0,0 +1,25 @@
+package com.banjjoknim.cleanarchitecture.user.domain
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+
+class UserTest {
+
+    @DisplayName("회원 이름 변경 테스트 케이스")
+    @Nested
+    inner class ChangeNicknameTestCases {
+        @Test
+        fun `회원 닉네임을 변경한다`() {
+            // given
+            val user = User(nickname = Nickname("banjjoknim"))
+
+            // when
+            user.changeNickname("colt")
+
+            // then
+            assertThat(user.nickname).isEqualTo(Nickname("colt"))
+        }
+    }
+}