How can I mock a Macro attribute in Rust - rust

Question

How can I mock a macro attribute when testing in Rust, is there some library to facilitate this?
For instance #[my_macro] modifies a struct applying another macro #[account()] to one of his fields, this macro doesn't exist in my library but exists in the programs which are using my macro:
// lib.rs
extern crate proc_macro;
use proc_macro::TokenStream;
mod macros;
#[proc_macro_attribute]
pub fn my_macro(args: TokenStream, input: TokenStream) -> TokenStream {
proc_macro::TokenStream::from(quote!(
pub struct MyModifiedStruct{
#[account()]
pub field1: u8
}
))
}
Now how can I test my_macro without getting an error for not having the #[account()] dependency in my library?
// tests/my_test.rs
#[test]
fn test_my_macro() {
#[my_macro]
pub struct MyStruct{}
let my_struct = MyStruct{field1:1}
assert_eq!(my_struct.field1, 1)
}
My normal approach in Python would be mocking the #[account()] attribute, but not sure how can that be done in Rust.

Answer 1

My normal approach in Python would be mocking the #[account()] attribute, but not sure how can that be done in Rust.
You could implement a mock version of your #[account] attribute macro in the same proc-macro crate as #[my_macro] is defined and import it into the scope you are using #[my_macro] in:
lib.rs:
extern crate proc_macro;
use proc_macro::TokenStream;
mod macros;
#[proc_macro_attribute]
pub fn my_macro(args: TokenStream, input: TokenStream) -> TokenStream {
proc_macro::TokenStream::from(quote!(
pub struct MyModifiedStruct{
#[account()]
pub field1: u8
}
))
}
#[proc_macro_attribute]
pub fn account(_args: TokenStream, input: TokenStream) -> TokenStream {
input
}
tests/my_test.rs:
// tests/my_test.rs
use your_crate::{my_macro, account};
#[test]
fn test_my_macro() {
#[my_macro]
pub struct MyStruct{}
let my_struct = MyStruct{field1:1}
assert_eq!(my_struct.field1, 1)
}