test: add unit tests for PlayerController and ShopController

- Add PlayerControllerTest to verify retrieval of all players and individual player by UUID.
- Add ShopControllerTest to verify retrieval of all shops and individual shop by item name.

src/test/java/com/slprojects/democultureconceptsinfo/PlayerControllerTest.java

+package com.slprojects.democultureconceptsinfo;
+
+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 java.util.UUID;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@WebMvcTest(PlayerController.class)
+public class PlayerControllerTest {
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    public void testGetAllPlayers() throws Exception {
+        mockMvc.perform(get("/players"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$").isArray())
+                .andExpect(jsonPath("$[0].username").value("JohnDoe"));
+    }
+
+    @Test
+    public void testGetPlayer() throws Exception {
+        UUID uuid = PlayerService.firstFakePlayer.getUuid();
+        mockMvc.perform(get("/player").param("uuid", uuid.toString()))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.username").value("JohnDoe"));
+    }
+}

src/test/java/com/slprojects/democultureconceptsinfo/ShopControllerTest.java

+package com.slprojects.democultureconceptsinfo;
+
+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.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@WebMvcTest(ShopController.class)
+public class ShopControllerTest {
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    public void testGetAllShops() throws Exception {
+        mockMvc.perform(get("/shops"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$").isArray())
+                .andExpect(jsonPath("$[0].itemName").value("Sword"));
+    }
+
+    @Test
+    public void testGetShop() throws Exception {
+        mockMvc.perform(get("/shop").param("itemName", "Sword"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.itemName").value("Sword"));
+    }
+}