add test for health controller

backend/src/test/java/de/szut/casino/health/HealthControllerTest.java

@@ -0,0 +1,26 @@
+package de.szut.casino.health;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+
+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.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.test.web.servlet.MockMvc;
+
+@WebMvcTest(HealthController.class)
+@AutoConfigureMockMvc(addFilters = false)
+public class HealthControllerTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    void healthCheckReturnsUpStatus() throws Exception {
+        mockMvc.perform(get("/health"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.status").value("UP"));
+    }
+}