Diblob: A Python framework for computations on digraphs as software models with focus on effective test case design

Directed graphs (digraphs) are one of the basic software models. In particular, they are used to design test cases based on certain graph coverage criteria. This paper introduces Diblob – a Python package designed for computations on digraphs, emphasizing use in software testing. It does not depend on external packages and operates on JSON representations of digraphs, which makes it a universal tool. Diblob allows for a hierarchical representation of digraph structures to create software models suitable for test cases requiring state machine coverage, abstracting – where necessary – from analyzing specific graph elements (e.g., strongly connected components). Diblob also implements several algorithms for achieving graph-based test coverage criteria.