Coverex is an Elixir Coverage tool used by mix. It provides tables with overviews of module and function coverage data, includings links to annotated source code files and supports coveralls.io.
PropCheck provides property based testing and is an Elixir layer around PropEr. It is also inspired by Quviq's QuickCheck Elixir library.
Reaxive is a library inspired by Reactive Extensions and ELM to provide functional reactive programming to Elixir. It allows for active sequences of events and a set of stream-reducer like transformations such as map or filter.