diff --git a/src/test/kotlin/com/sangdol/validation/DemoControllerTest.kt b/src/test/kotlin/com/sangdol/validation/DemoControllerTest.kt
index 2ef97cf..2383c1f 100644
--- a/src/test/kotlin/com/sangdol/validation/DemoControllerTest.kt
+++ b/src/test/kotlin/com/sangdol/validation/DemoControllerTest.kt
@@ -21,7 +21,7 @@ import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
 class DemoControllerTest {
 
     @Autowired
-    private val mockMvc: MockMvc? = null
+    private lateinit var mockMvc: MockMvc
 
     @DisplayName("Wrapper 타입인 경우 값이 입력되지 않으면 HttpMessageNotReadableException이 발생한다.")
     @ParameterizedTest(name = "{0}")