### Question:
CostManagementImpl implements CostManagementService { @Override public CommonResult insertCost(Cost cost) { int count = costMapper.insertSelective(cost); if (count == 0) { return CommonResult.fail(); } return CommonResult.success(count); }  @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 testInsertCost() throws Exception { }