The #[ip_test] and #[ip_addr_test] macros

The #[ip_test] and #[ip_addr_test] macros provide a shorthand to define tests that are parameterized and need to run on both IP versions.

We will use #[ip_test] in this explanation, but the same explanation applies just as well to #[ip_addr_test].

You can define a test that is parameterized over an IP version as follows:

#[ip_test]
fn test_foo<I: Ip>() {
   assert!(do_ip_specific_thing::<I>());
   /* ... */
}

A function marked with #[ip_test] or #[ip_addr_test] must always:

• Receive zero arguments
• Have exactly one type parameter that
  • Has an Ip trait bound for #[ip_test]
  • Has an IpAddress trait bound for #[ip_addr_test]

The #[ip_test] and #[ip_addr_test] macros generate code from that example that looks like:

fn test_foo<I: Ip>() {
   assert!(do_ip_specific_thing::<I>());
   /* ... */
}

#[test]
fn test_foo_v4() {
   test_foo::<Ipv4>();
}

#[test]
fn test_foo_v6() {
   test_foo::<Ipv6>();
}

For test attributes, you can just add them as you would for a regular test:

#[ip_test]
#[should_panic]
fn test_foo_panics<I: Ip>() {
    /* ... */
   do_ip_thing_that_panics::<I>();
}