src/test/java/com/example/demo/controller/HelloControllerTest.java

@@ -0,0 +1,38 @@
+package com.example.demo.controller;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@WebMvcTest(HelloController.class)
+class HelloControllerTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    void hello_withoutName_returnsDefaultMessage() throws Exception {
+        mockMvc.perform(get("/hello"))
+                .andExpect(status().isOk())
+                .andExpect(content().string("Hello, World!"));
+    }
+
+    @Test
+    void hello_withName_returnsPersonalizedMessage() throws Exception {
+        mockMvc.perform(get("/hello").param("name", "Spring"))
+                .andExpect(status().isOk())
+                .andExpect(content().string("Hello, Spring!"));
+    }
+
+    @Test
+    void hello_withBlankName_returnsDefaultMessage() throws Exception {
+        mockMvc.perform(get("/hello").param("name", "   "))
+                .andExpect(status().isOk())
+                .andExpect(content().string("Hello, World!"));
+    }
+}