Add AbstractControllerTest for shared test utilities

Introduce an abstract base test class to centralize and simplify common test setup for controller tests. This includes MockMvc auto-configuration to streamline testing in Spring WebMvcTest contexts.

Author: Ahn-JoonHun

spring-boot/src/test/java/com/mpc/springboot/shared/AbstractControllerTest.java

@@ -0,0 +1,14 @@
+package com.mpc.springboot.shared;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.test.web.servlet.MockMvc;
+
+@WebMvcTest
+@AutoConfigureMockMvc
+public abstract class AbstractControllerTest {
+
+    @Autowired
+    protected MockMvc mockMvc;
+}