Macro assert_always 

macro_rules! assert_always {
    ($condition:expr, $message:expr$(, $details:expr)?) => { ... };
    ($($rest:tt)*) => { ... };
}

Assert that condition is true every time this function is called, and that it is called at least once. The corresponding test property will be viewable in the Antithesis SDK: Always group of your triage report.

Example

use serde::Serialize;
use antithesis_sdk::{assert_always, random};

// Details can be any Serialize type, and are only serialized when the
// assertion actually emits — on a sparse sample of passing and failing
// evaluations. A plain struct of values and references like this
// therefore costs nothing on the hot path.
#[derive(Serialize)]
struct Details<'a> {
    max_allowed: u64,
    actual: u64,
    source: &'a str,
}

const MAX_ALLOWED: u64 = 100;
let actual = random::get_random() % 100u64;
let details = Details { max_allowed: MAX_ALLOWED, actual, source: "demo" };
antithesis_sdk::assert_always!(actual < MAX_ALLOWED, "Value in range", &details);

Ensure that non-const-evaluable messages are rejected.

use serde_json::json;
const MESSAGE: &str = concat!("Value", " in range");
antithesis_sdk::assert_always!(true, MESSAGE, &json!({}));

A message computed at runtime is rejected at compile time:

use serde_json::json;
let message = String::from("Value in range");
antithesis_sdk::assert_always!(true, message, &json!({}));

use serde_json::json;
antithesis_sdk::assert_always!(true, format!("{}", "Value in range"), &json!({}));