Crate assert_not 

assert_not - Inverse Assertion Macros for Rust

This crate provides macros for asserting that conditions are NOT true, which is the inverse behavior of Rust’s standard assert! macro.

Why use assert_not?

While assert! verifies that a condition is true, sometimes you need to ensure that a condition is explicitly false. Instead of writing assert!(!condition), assert_not!(condition) provides clearer intent and better readability.

Features

• assert_not! - Runtime assertion that panics if condition is true
• debug_assert_not! - Debug-only assertion (removed in release builds)
• no_std compatible - Works in embedded and bare-metal environments
• Zero runtime overhead in release builds (for debug variants)
• Custom error messages with format string support

Quick Start

Add to your Cargo.toml:

# For tests (most common)
[dev-dependencies]
assert-not = "0.1.0"

# For runtime use
[dependencies]
assert-not = "0.1.0"

Basic usage:

use assert_not::assert_not;

assert_not!(false);  // ✓ Passes
let x = 5;
assert_not!(x == 0, "x should not be zero");  // ✓ With message

Common Use Cases

use assert_not::assert_not;

#[derive(PartialEq)]
enum Status { Error, Ok }

let value = 10;
let state = Status::Ok;
let config = Some("config");

// Input validation
assert_not!(value < 0, "Value must be positive");

// State validation
assert_not!(state == Status::Error, "Cannot proceed in error state");

// Optional values
assert_not!(config.is_none(), "Configuration required");

Comparison with Standard Assertions

use assert_not::assert_not;
 
let x = 5;
let list = vec![1, 2, 3];

// Instead of:
assert!(x != 0);
assert!(!list.is_empty());

// You can write:
assert_not!(x == 0);
assert_not!(list.is_empty());

Modules

examples

More Examples

Macros

assert_not

Asserts that a condition is NOT true.

debug_assert_not

Debug-only version of assert_not!.