Crap4DotNet 0.2.0

Crap4DotNet

A .NET global tool that computes CRAP (Change Risk Anti-Patterns) scores for your C# code.

CRAP combines cyclomatic complexity with code coverage to identify methods that are both complex and poorly tested — the riskiest code in your project.

Install

dotnet tool install -g Crap4DotNet

Requires .NET 8.0 or later.

Usage

# Run tests and analyze in one step
dotnet-crap analyze ./MyApp.sln --run-tests

# Analyze with explicit coverage file
dotnet-crap analyze ./src/MyProject --coverage ./TestResults/coverage.cobertura.xml

# Write report to file
dotnet-crap analyze ./src/MyProject --coverage ./coverage.xml --output report.json

# Custom threshold for one run (default: 30)
dotnet-crap analyze ./src/MyProject --coverage ./coverage.xml --threshold 15

# Compare two reports
dotnet-crap diff before.json after.json

Microsoft.Testing.Platform

--run-tests uses the VSTest coverage collector. When global.json selects Microsoft.Testing.Platform as the test runner, it exits 2 with UNSUPPORTED_TEST_RUNNER. Generate Cobertura coverage with the Microsoft.Testing.Extensions.CodeCoverage package and pass it with --coverage.

Configuration

To set a project's threshold, commit a crap4dotnet-config.json at its root. analyze uses the nearest one in the analyzed path's directory or a parent. --threshold overrides it.

{
  "crap": {
    "threshold": 30
  }
}

Exit Codes

CRAP Formula

CRAP(m) = complexity(m)^2 * (1 - coverage(m))^3 + complexity(m)

A method with complexity 1 and full coverage has a CRAP score of 1 (perfect). A method with complexity 20 and 10% coverage has a CRAP score of ~312 (terrible).

JSON Output

The tool outputs a JSON report with method-level CRAP scores, statistics, severity bands, and a namespace hierarchy. See the specification for the full schema.