Infection vs Muter

Infection is a PHP mutation-testing library that shows which changes a test suite fails to detect. It creates mutants using predefined operators, runs tests against changed code, and records killed and escaped mutants, errors, and timeouts. Its Mutation Score Indicator measures the share of generated mutations detected by tests; it also reports Mutation Code Coverage and Covered Code Mutation Score Indicator. Infection supports PHPUnit, PhpSpec, Codeception, and Testo, and runs from the command line at a project root. Teams can run mutated tests in parallel, focus analysis on touched lines or files, and set minimum mutation-score thresholds that fail a build. The homepage describes more than 100 mutators grouped into profiles and allows custom mutators. Optional PHPStan and Mago integrations can help catch escaped mutants involving type violations, dead code, and unreachable paths. Installation options include PHAR, Phive, Composer, Git, and Homebrew. A browser playground supports trying PHP code and tests without installing the tools. Infection is free under the BSD-3-Clause license and requires PHP 8.3 or newer plus Xdebug, phpdbg, or pcov.

Muter is a free, open-source mutation testing utility for Swift test suites on macOS. It changes code in a complete copy of the codebase, leaving the original untouched, then reports mutation scores for the full suite and individual files. Runs can happen in Xcode, from the command line or incrementally in continuous integration. Configuration covers Xcode projects, workspaces and Swift Package Manager. Reports can be plain text, JSON, HTML or Xcode issue navigator results, including surviving mutants. Documented operators replace relational operators, remove side effects, change logical connectors and swap ternary expressions. Muter supports projects tested with xcodebuild, including iOS, macOS, tvOS and watchOS applications, but the utility runs only on macOS 10.15 or newer. It supports Swift, not Objective-C. Any test target or suite can be used with Swift application code, although UI tests may take a long time. The project states that it has no network access and collects no analytics.