Add Mutation Testing

Setup mutation testing framework with quality metrics and CI integration: $ARGUMENTS

Current Testing Context

• Language: !find . -name "*.js" -o -name "*.ts" | head -1 >/dev/null && echo "JavaScript/TypeScript" || find . -name "*.py" | head -1 >/dev/null && echo "Python" || find . -name "*.java" | head -1 >/dev/null && echo "Java" || echo "Multi-language"
• Test coverage: !find . -name "coverage" -o -name ".nyc_output" | head -1 || echo "No coverage data"
• Test framework: !grep -l "jest\\|mocha\\|pytest\\|junit" package.json pom.xml setup.py 2>/dev/null | head -1 || echo "Detect from tests"
• CI system: !find . -name ".github" -o -name ".gitlab-ci.yml" -o -name "Jenkinsfile" | head -1 || echo "No CI detected"

Task

Implement comprehensive mutation testing with framework optimization and quality gates:

Language Focus: Use $ARGUMENTS to specify JavaScript, Java, Python, Rust, Go, C#, or auto-detect from codebase

Mutation Testing Framework:

1. Tool Selection & Setup - Choose framework (Stryker, PIT, mutmut, cargo-mutants), install dependencies, configure basic settings, validate installation
2. Mutation Operator Configuration - Configure arithmetic operators, relational operators, logical operators, conditional boundaries, statement mutations
3. Performance Optimization - Setup parallel execution, configure incremental testing, optimize file filtering, implement caching strategies
4. Quality Metrics - Configure mutation score calculation, setup survival analysis, implement threshold enforcement, track effectiveness trends
5. CI/CD Integration - Automate execution triggers, configure performance monitoring, setup result reporting, implement deployment gates
6. Result Analysis - Setup visualization dashboards, configure surviving mutant analysis, implement remediation workflows, track regression patterns

Advanced Features: Selective mutation testing, performance profiling, automated test improvement suggestions, mutation trend analysis, quality gate integration.

Framework Support: Language-specific optimizations, tool ecosystem integration, performance tuning, reporting customization.

Output: Complete mutation testing setup with configured framework, CI integration, quality thresholds, and analysis workflows.