Mutant: Contributor's guide

Hi, thanks for opening the contributor's guide. The goal of this document is to discuss how Mutant works internally. After reading this document you should be able to extend Mutant and contribute changes to its source code. If that's not the case, please send a patch fixing it!

lein-mutate: Leiningen plugin

in which lein-mutate is presented as a shallow layer atop mutant proper

The library itself

some copy-pasta from the readme below

API

The public API consists of two functions and one helper.

(mutant.core/run source-directory test-directory test-fn)

Subjects code in source-directory to mutation testing. After each mutation it reloads relevant namespaces found in source-directory and test-directory and invokes test-fn. test-fn should throw or return a falsey value upon failure.

Returns a lazy seq of maps of results consisting of following keys:

• :total is the total number of generated mutants so far, and
• :survivors is a sequence of mutants which didn't cause test-fn to report failure. Each mutant is a map with following keys:
  • :ns is the mutant's namespace,
  • :original is the original form, and
  • :mutant is the mutated form.

(mutant.core/pprint results)

Pretty-prints results returned by mutant.core/run.

(mutant.helpers.clojure-test/test-fn)

A simple wrapper around clojure.test/run-all-tests, which makes it return false in case of any failures or errors. An optional argument is a regular expression passed to clojure.test/run-all-tests.

Mutation testing mutant

and now the tricky bit