vivian-essentials 0.1.0

vivian's essential utilities
Documentation 
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use std::{
    error::Error,
    fmt::{Display, Formatter, Result as FmtResult},
};

#[derive(Clone, Debug)]
pub struct GuardError;

impl Error for GuardError {}

impl Display for GuardError {
    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
        f.write_str("guard condition failed")
    }
}

pub fn guard(boolean: bool) -> Result<(), GuardError> {
    if boolean {
        Ok(())
    } else {
        Err(GuardError {})
    }
}

#[cfg(test)]
mod tests {
    use super::GuardError;
    use std::fmt::Debug;

    static_assertions::assert_impl_all!(GuardError: Clone, Debug, Send, Sync);

    #[test]
    fn success() {
        assert!(super::guard(true).is_ok());
    }

    #[test]
    fn failure() {
        assert!(super::guard(false).is_err());
    }
}