### Question:
CostManagementImpl implements CostManagementService { @Override public CommonResult listAllCosts() { List<Cost> list = costMapper.list(); return CommonResult.success(list); }  @Override CommonResult listAllCosts(); @Override CommonResult getCostById(Integer id); @Override CommonResult insertCost(Cost cost); @Override CommonResult updateCostById(Cost cost); @Override CommonResult deleteCostById(Integer id);  }### Answer:
@Test public void testListAllCosts() throws Exception { }