Macro coverage_test_alias

macro_rules! coverage_test_alias {
    ($name:ident {
        alias_and_mode: $alias_and_mode:expr, // &'static str
        default: $default:expr, // bool
        only_hosts: $only_hosts:expr $(,)? // bool
    }) => { ... };
}

Declares an alias for running the Coverage tests in only one mode. Adapted from test_definitions.