Software testing depends on effective oracles. Implicit oracles, such as checks for program crashes, are widely applicable but narrow in scope. Oracles based on formal specifications can reveal application-specific failures, but specifications are expensive to obtain and maintain. Metamorphic oracles are somewhere in-between. They test equivalence among different procedures to detect semantic failures. Until now, the identification of metamorphic relations has been a manual and expensive process, except for few specific domains where automation is possible. We present MeMo, a technique and a tool to automatically derive metamorphic equivalence relations from natural language documentation, and we use such metamorphic relations as oracles in automatically generated test cases. Our experimental evaluation demonstrates that 1) MeMo can effectively and precisely infer equivalence metamorphic relations, 2) MeMo complements existing state-of-the-art techniques that are based on dynamic program analysis, and 3) metamorphic relations discovered with MeMo effectively detect defects when used as test oracles in automatically-generated or manually-written test cases.

软件测试依赖于有效的预言机。隐式预言机，例如检查程序崩溃，应用广泛但范围狭窄。基于正式规范的 Oracle 可以揭示特定于应用程序的故障，但获取和维护规范的成本很高。变形神谕介于两者之间。他们测试不同程序之间的等效性以检测语义故障。到目前为止，除了少数可以自动化的特定领域外，变形关系的识别一直是一个手动且昂贵的过程。我们提出了 MeMo，一种从自然语言文档中自动推导出变形等价关系的技术和工具，我们在自动生成的测试用例中使用这种变形关系作为预言机。