Abstract Due to the ever-increasing adaptation of Blockchain technologies in the private, public, and business domains, both the use of Distributed Systems and the increased demand for their reliability has exploded recently, especially with their desired integration with Internet-of-Things devices. This has resulted in a lot of work being done in the fields of distributed system analysis and design, specifically in the areas of blockchain smart contract design and formal verification. However, the focus on formal verification methodologies has meant that less attention has been given toward more traditional testing methodologies, such as unit testing and integration testing. This includes a lack of full support by most, if not all, the major blockchain implementations for testing at scale, except on fully public test networks. This has several drawbacks, such as: (1) The inability to do repeatable testing under identical scenarios, (2) reliance upon public mining of blocks, which introduces unreasonable amounts of delay for a test driven development scenario that a private network could reduce or eliminate, and (3) the inability to design scenarios where parts of the network go down. In this chapter we discuss design, testing methodologies, and tools to allow Testing at Scale of IoT Blockchain Applications.