Cargo.toml

[package]
name = "my-crate"
version = "0.1.0"
edition = "2018"

[lib]
proc-macro = true
path = 'lib.rs'

[[test]]
name = 'smoke'
path = 'test.rs'

[dependencies]
syn = { version = "0.15.23", features = ["full"] }
quote = "0.6.10"

[dev-dependencies]
env_logger = "0.6.0"
log = "0.4.6"

lib.rs

extern crate proc_macro;

use proc_macro::TokenStream;

#[proc_macro_attribute]
pub fn my_test(_attr: TokenStream, item: TokenStream) -> TokenStream {
    let f = syn::parse_macro_input!(item as syn::ItemFn);

    let attrs = &f.attrs;
    let ident = &f.ident;
    let block = &f.block;
    (quote::quote! {
        #(#attrs)*
        #[test]
        fn #ident() {
            drop(env_logger::try_init());
            #block
        }
    }).into()
}

test.rs

#[my_crate::my_test]
fn smoke() {
    log::debug!("hello");
}