@Operation(summary = "get", description = "Get a cluster")
    @GetMapping("/{id}")
    public ResponseEntity<ClusterVO> get(@PathVariable Long id) {
        return ResponseEntity.success(clusterService.get(id));
    }
@Test
    void getReturnsNotFoundForInvalidId() {
        Long id = 999L;
        when(clusterService.get(id)).thenReturn(null);

        ResponseEntity<ClusterVO> response = clusterController.get(id);

        assertTrue(response.isSuccess());
        assertNull(response.getData());
    }