NEuler is an open source application integrated within Neo4j Desktop, whose code is available on GitHub at https://github.com/neo4j-apps/neuler.
It is a very powerful tool allowing us to test all the algorithms implemented in the GDS, from path finding (Chapter 4, The Graph Data Science Library and Path Finding) and centrality (Chapter 5, Node Importance) to community detection and similarity. It also enables visualizing the results with a graph visualization feature based upon neoviz.js.
Installation instructions are available in the GitHub repository of this book.