catchorg/Catch2
Summary
Catch2 is a widely used unit testing framework for C++ that emphasizes a simple syntax, natural test expressions, and local setup/teardown via sections. The repo page outlines what Catch2 is, how to build and use it, and notes on the v3 migration where Catch2 becomes a multi-header library rather than a single-header distribution. It also points to tutorials, documentation, releases, and ways to contribute.