Add IgnoreErr variant to Unwrap enum

[apollo-sturdy]

No description provided.

[pacmanifold]

/// An enum to choose which type of unwrap to use. When using `Unwrap::Err`, the
/// result must be an `Err` or the test will panic. If the result contains an
/// `Err`, the test will pass only if the error message contains the provided
/// string.
pub enum Unwrap {
    /// Unwrap the result, expecting it to be `Ok`.
    Ok,
    /// Unwrap the result, expecting it to be `Err`. The error message must
    /// contain the provided string.
    Err(&'static str),
    /// Call `ok()` on the result, returning `None` if it is an `Err`.
    IgnoreErr,
}

impl Unwrap {
    pub fn unwrap<T: Debug, E: Debug>(self, result: Result<T, E>) -> Option<T> {
        match self {
            Unwrap::Ok => {
                let res = result.unwrap();
                Some(res)
            }
            Unwrap::Err(s) => {
                let err = result.unwrap_err();
                assert!(
                    format!("{:?}", err).contains(s),
                    "Expected error message to contain {:?}, got {:?}",
                    s,
                    err
                );
                None
            }
            Unwrap::IgnoreErr => result.ok(),
        }
    }
}