#[cfg(not(any(test, feature="extra_checks")))]
macro_rules! test_assert {
($cond:expr) => ({ });
($cond:expr,) => ({ });
($cond:expr, $($arg:tt)+) => ({ });
}
#[cfg(any(test, feature="extra_checks"))]
macro_rules! test_assert {
($cond:expr) => ({ assert!($cond); });
($cond:expr,) => ({ assert!($cond); });
($cond:expr, $($arg:tt)+) => ({ assert!($cond, $($arg)*); });
}