Purpose: PropEr is a tool for automated, semi-random, property-based testing of Erlang programs.
Targeted testing: Recent releases support targeted property-based testing, which brings search-based testing techniques into property-based testing.
Erlang types: Erlang type declarations can be used as input specifications, and PropEr can generate data from them.
Automatic testing: PropEr can test functions automatically using information in their Erlang specifications.
Properties: Properties are written using Erlang expressions with predefined macros.
Installation: The user guide describes obtaining source from GitHub, compiling it with make, or installing it with Homebrew.
Integrations: The user guide explains using PropEr with EUnit and describes handling a shared ?LET macro and captured output.
License: PropEr is open-source software distributed under the GPL, version 3 or later.
Support: The developers invite comments, suggestions, feature requests, bug reports, patches, and other contributions through the project website, GitHub, or email.
Known limitation: PropEr's generator language and Erlang type language differ for list expressions, allowing generators to specify lists of particular lengths and element types.
Constraints: Constraints that cannot be expressed in Erlang's type language can be expressed with custom generators; the FAQ cautions that filtering may keep trying random values until one passes.
Intended users: PropEr is designed for testing programs written in Erlang, with a focus on pure functions and library modules for stateful code.
Price from: Free

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Sources

proper-testing.github.io· checked 5 Oct 2026
proper-testing.github.io/userguide.html· checked 5 Oct 2026
proper-testing.github.io/faq.html· checked 5 Oct 2026