@stacks/rendezvous

Rendezvous rv: The Clarity Fuzzer

Rendezvous rv is a Clarity fuzzer designed to cut through your smart contract's defenses with precision. Uncover vulnerabilities with unmatched power and intensity. Get ready to meet your contract's vulnerabilities head-on.

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- Node.js: Supported versions include 20, 22, and 24. Other versions may work, but they are untested.

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The rv fuzzer, inspired by John Hughes' paper _"Testing the Hard Stuff and Staying Sane"_[^1], ensures contract robustness with Clarity invariants and tests.

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

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`
npm install @stacks/rendezvous
`

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`
npx rv
`

---

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Positional arguments:

- path-to-clarinet-project - Path to the root directory of the Clarinet project (where Clarinet.toml exists).
- contract-name - Name of the contract to test, per Clarinet.toml.
- type - Type of test to run. Options:
- test - Run property-based tests.
- invariant - Run invariant tests.

Options:

- --seed – The seed to use for the replay functionality.
- --runs – The number of test iterations to use for exercising the contracts.
(default: 100)
- --bail – Stop after the first failure.
- --dial – The path to a JavaScript file containing custom pre- and
post-execution functions (dialers).

---

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Here's an example of a test that checks reversing a list twice returns the original:

`clarity
(define-public (test-reverse-list (seq (list 127 uint)))
(begin
(asserts!
(is-eq seq
(reverse-uint
(reverse-uint seq)))
(err u999))
(ok true)))
`

You can run property-based tests using rv with the following command:

`
rv example reverse test
`

---

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Here's a Clarity invariant to detect a bug in the example counter contract:

`clarity
(define-read-only (invariant-counter-gt-zero)
(let
((increment-num-calls (default-to u0 (get called (map-get? context "increment"))))
(decrement-num-calls (default-to u0 (get called (map-get? context "decrement")))))
(if (> increment-num-calls decrement-num-calls)
(> (var-get counter) u0)
true)))
`

You can run invariant tests using rv with the following command:

`
rv example counter invariant
``

---

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For full documentation, see the official Rendezvous Book.

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[^1]: Hughes, J. (2004). _Testing the Hard Stuff and Staying Sane_. In Proceedings of the ACM SIGPLAN Workshop on Haskell (Haskell '04).