Feature Flags

All of Cnpj’s optional integrations are off by default and purely additive — enabling one never changes what counts as a valid CNPJ, only what you can do with a Cnpj once you have one.

[dependencies]
ftracker-identifiers = { version = "0.0.1", features = ["serde", "schemars", "arbitrary", "proptest"] }

serde

(De)serializes Cnpj as its compact 14-character string (e.g. "12ABC34501DE35") — never the punctuated form, so it round-trips as a plain identifier in JSON, YAML, or config files.

Deserialization always re-runs full validation: an untrusted payload (a malformed API request, a hand-edited config file) can never produce an invalid Cnpj. A bad value fails to deserialize with a descriptive error instead of silently producing garbage.

use ftracker_identifiers::Cnpj;

let cnpj = Cnpj::parse("00.000.000/0001-91").unwrap();
let json = serde_json::to_string(&cnpj).unwrap();
assert_eq!(json, "\"00000000000191\"");

let back: Cnpj = serde_json::from_str(&json).unwrap();
assert_eq!(cnpj, back);

// Invalid input is rejected at deserialization time, not silently accepted.
assert!(serde_json::from_str::<Cnpj>("\"not-a-cnpj\"").is_err());

schemars

Implements JsonSchema for Cnpj, so it can appear in a generated OpenAPI/JSON Schema document as a pattern-constrained string rather than an opaque string type. This feature implies serde.

The generated schema:

{
  "type": "string",
  "format": "cnpj",
  "minLength": 14,
  "maxLength": 14,
  "pattern": "^[A-Z0-9]{12}[0-9]{2}$",
  "description": "Brazilian CNPJ (Cadastro Nacional da Pessoa Jurídica), unformatted, Módulo 11 checksum-valid."
}

Note that the pattern alone doesn’t capture the Módulo 11 checksum constraint — schema validators outside this crate (API gateways, other-language clients) can reject malformed shapes, but true checksum validation still requires this crate (or a reimplementation of the same algorithm; see Structure & Formats).

arbitrary

Implements Arbitrary for Cnpj, so fuzz targets (e.g. via cargo fuzz) can generate structurally valid, checksum-correct Cnpj values directly, instead of generating raw strings that mostly fail validation before reaching the code under test.

proptest

Exposes reusable proptest strategies at ftracker_identifiers::cnpj::proptest:

• cnpj::proptest::valid_cnpj() — a Strategy<Value = Cnpj> producing checksum-correct values spanning both the numeric and alphanumeric formats.
• cnpj::proptest::valid_cnpj_formatted_string() — the same, rendered as a punctuated String, useful for round-trip-through-formatting property tests.

This is the recommended way to property-test your own code that accepts a Cnpj, without hand-rolling a checksum-valid generator:

use ftracker_identifiers::{cnpj::proptest::valid_cnpj, Cnpj};
use proptest::proptest;

proptest! {
    #[test]
    fn my_function_accepts_any_valid_cnpj(cnpj in valid_cnpj()) {
        // exercise your own code with `cnpj` here
    }
}