How to Use Test Helpers and Shared Test Utilities

Testing
2026-04-17T12:05:42+00:00
Use #[test] attributes and shared modules to define reusable helper functions for your Rust test suite.

Use the #[test] attribute on helper functions and place shared utilities in a tests module or a separate crate to reuse them across your test suite.

#[cfg(test)]
mod tests {
    use super::*;

    // Shared helper function
    fn setup_data() -> Vec<i32> {
        vec![1, 2, 3]
    }

    #[test]
    fn test_helper_usage() {
        let data = setup_data();
        assert_eq!(data.len(), 3);
    }

    #[test]
    fn test_another_helper_usage() {
        let data = setup_data();
        assert!(data.contains(&2));
    }
}

For larger projects, create a separate crate (e.g., test-utils) and add it as a dev-dependency in Cargo.toml, then import it with use test_utils::setup_data;.