Mull

Mull is a practical mutation testing and fault injection tool for C and C++. It requires no changes to the code, the tests or the build system, only a few compiler flags.

Mutations are applied at compile time with the LLVM toolchain, and the mull-runner tool executes the tests against each mutant while mull-reporter presents the results. Filters limit mutations to relevant code, and Git-aware scoping, build failure on regressions and GitHub annotations integrate it with CI. Mutation testing is recommended by safety standards such as ISO 26262 and IEC 61508, which makes Mull relevant for embedded and safety-critical software.

Mull is free and open source under the Apache 2.0 licence.