Software testing models and improvement of X-model

The X-model was improved by increasing the unit test criteria based on analysing features and limitations of the V-model,W-modle and X-model.The improved X-model was applied to a small educational management system.The results showed that the improved X-model could reduce the rate of the passed program fragments,prevent error from being magnified and reduce iteration workload which was brought by requirements change and turnover of developers.