We present a metamorphic testing approach to validate the information included in OpenStreetMap, a collaborative effort to produce a free map of the world. We focus on the quality of the tags storing the information about the elements of the map. We identified metamorphic relations with the potential to detect different types of tagging errors. In particular, we carefully designed mechanisms to automatically generate follow-up inputs, a fundamental component in the successful application of a metamorphic testing approach. The intrinsic nature of automatically analysing tags implies that we will detect real errors but some false positives as well. In order to obtain a good trade-off between real errors and false positives, we introduce thresholds. Our MRs will raise an error associated with a certain value if, depending on the nature of the MR, we have a certain number of elements (not) fulfilling a given condition. In order to evaluate the goodness and versatility of our framework, we chose four cities in different continents with the goal of analysing very heterogeneous contributors adding information in different languages. The application of this framework to the analysis of the chosen cities revealed errors in all of them and in all the considered categories. In addition, around 66% of the errors found by our MRs in the analysed areas have not been previously reported by Osmose, the de facto standard OSM error checker.

中文翻译：

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使用变形测试来提高 OpenStreetMap 中标签的质量


我们提出了一种变质​​测试方法来验证 OpenStreetMap 中包含的信息，这是一项制作免费世界地图的协作努力。我们关注存储地图元素信息的标签的质量。我们发现变质关系具有检测不同类型标记错误的潜力。特别是，我们精心设计了自动生成后续输入的机制，这是成功应用变质测试方法的基本组成部分。自动分析标签的本质意味着我们将检测到真正的错误，但也会检测到一些误报。为了在真实错误和误报之间获得良好的权衡，我们引入了阈值。如果根据 MR 的性质，我们有一定数量（不）满足给定条件的元素，我们的 MR 将引发与特定值相关的错误。为了评估我们框架的优点和多功能性，我们选择了不同大陆的四个城市，目的是分析以不同语言添加信息的非常异构的贡献者。将该框架应用于对所选城市的分析揭示了所有城市和所有考虑的类别中的错误。此外，我们的 MR 在分析区域发现的错误中，大约 66% 之前并未被事实上的标准 OSM 错误检查器 Osmose 报告过。