assert_that!(Some("foobar")).some().starts_with("foo");

assert_that!(Ok::<&str, ()>("ok_value"))
    .ok()
    .starts_with("ok");
assert_that!(Err::<(), &str>("err msg"))
    .err()
    .starts_with("err");

assert_that!(anyhow!("error message")).has_message("error message");

assert_that!(Cow::Borrowed("foobar")).deref().starts_with("foo");

let tree_map = BTreeMap::from([("hello", "sorted_map"), ("world", "in")]);
assert_that!(tree_map)
    .contains_exactly_in_order(BTreeMap::from([("hello", "sorted_map"), ("world", "in")]));

assert_that!(BTreeSet::from([1, 2, 3])).contains_all_of_in_order(BTreeSet::from([1, 2, 3]));

assert_that!(vec![1]).is_not_empty();