Macro assert_ok

macro_rules! assert_ok {
    ( $x:expr $(,)? ) => { ... };
    ( $x:expr, $y:expr $(,)? ) => { ... };
}

Panic if an expression doesn’t evaluate to Ok.

Used as assert_ok!(expression_to_assert, expected_ok_expression), or assert_ok!(expression_to_assert) which would assert against Ok(()).