This work presents our approach to formally model the Swiftaid system design, a digital platform that enables donors to automatically add Gift Aid to donations made via card payments. Following principles of Behaviour-Driven Development, we use Gherkin to capture requirements specified in legislation, specifically the UK Charity (Gift Aid Declarations) Regulations 2016. The Gherkin scenarios provide a basis for subsequent formal modelling and analysis using Event-B, Rodin and ProB. Interactive model simulations assist communication between domain experts, software architects and other stakeholders during requirements capture and system design, enabling the emergent system behaviour to be validated. Our approach was employed within the development of the real Swiftaid product, launched by Streeva in February 2019. Our analysis helped conclude that there was not a strong enough business case for one of the features, whichwas shown to provide nominal user convenience at the expense of increased complexity. This work provides a case study in allying formal and agile software development to enable rapid development of robust software.

中文翻译：

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使用 Event-B 的礼品援助系统的立法驱动开发

这项工作展示了我们对 Swiftaid 系统设计进行正式建模的方法，这是一个数字平台，使捐赠者能够自动将 Gift Aid 添加到通过卡支付的捐赠中。遵循行为驱动开发的原则，我们使用 Gherkin 来捕捉立法中规定的要求，特别是 2016 年英国慈善（礼品援助声明）条例。Gherkin 场景为后续使用 Event-B、Rodin 和 ProB 的正式建模和分析提供了基础. 交互式模型模拟有助于在需求捕获和系统设计期间在领域专家、软件架构师和其他利益相关者之间进行交流，从而能够验证紧急系统行为。我们的方法被用于开发真正的 Swiftaid 产品，该产品由 Streeva 于 2019 年 2 月推出。我们的分析有助于得出结论，其中一项功能没有足够强大的业务案例，这表明以增加复杂性为代价提供名义上的用户便利。这项工作提供了一个案例研究，将正式和敏捷的软件开发结合起来，以实现健壮软件的快速开发。