Introduction

Rendezvous (rv) is a fuzzer designed specifically for Clarity smart contracts. As the name suggests, it serves as a meeting point between your contracts and potential vulnerabilities, allowing you to discover and address issues before they can be exploited in production.

The tool focuses on two primary testing methodologies:

  1. Property-based testing: Verifying that specific properties of your contract hold true across a wide range of possible inputs.
  2. Invariant testing: Ensuring that certain conditions about your contract's state remain true regardless of the sequence of operations performed.

Why You Need Rendezvous

Smart contracts are immutable once deployed, making post-deployment fixes expensive or impossible. Traditional testing methods often fall short in discovering edge cases that might lead to security vulnerabilities or unexpected behavior. Rendezvous addresses these challenges by:

  • Exploring the unexpected: Through fuzzing, Rendezvous generates and tests a diverse range of inputs that developers might not consider during manual testing.
  • Finding edge cases: By repeatedly testing your contract with varying inputs, it can discover boundary conditions and rare scenarios that could cause issues.
  • Validating invariants: It ensures that your contract's core properties remain consistent regardless of the operations performed.
  • Helping reduce impedance mismatch: By testing in Clarity when possible while using TypeScript when needed (e.g., for events). Rendezvous dialers (Chapter 6) bridge the gap.

Project Philosophy

Rendezvous is built on the principles of simplicity, robustness, and developer-friendliness. We value:

  • Clarity first: Testing should happen in the same language as implementation whenever possible.
  • Simple, focused tests: Each test should verify one thing and do it well.
  • Community-driven development: Contributions from the community are essential to the project's success.

As noted in our contributing guidelines, we believe in handcrafted code with a purpose. Each file in the project is maintained with care, focusing on readability and maintainability. Our coding style emphasizes simplicity, clear American English, and concise logic.

Project Structure

Rendezvous integrates seamlessly with Clarinet projects, looking for test files alongside your contract implementations:

root
├── Clarinet.toml
├── contracts
│   ├── contract.clar
│   ├── contract.tests.clar
└── settings
    └── Devnet.toml

This structure allows for a natural workflow where tests live close to the code they're testing, making it easier to maintain both in tandem.

In the following chapters, we'll explore why testing directly in Clarity is beneficial, the testing methodologies employed by Rendezvous, how to install and use the tool, and examples of effective testing patterns.