Unable to run Rust unittests on binded library about node-bindgen HOT 5 OPEN

Hi @ziv, thanks for opening the issue, and for the great reproduction! I think I see two things happening here:

1. You are importing node_bindgen::derive::node_bindgen at the top-level module, but you are trying to use it inside your example module. Try putting your use statement inside of each module where you use #[node_bindgen].

2. I tried fixing 1 and then saw a new error:

error[E0432]: unresolved import `crate::example::sum`
 --> src/testing.rs:1:5                              
  |
1 | use crate::example::sum;
  |     ^^^^^^^^^^^^^^^^^^^ no `sum` in `example`

error: aborting due to previous error

I think this is due to the fact that node_bindgen actually reads your function body and generates a totally different function from it, which is intended to be called from node rather than Rust. For unit testing, I would suggest making an inner Rust function that does your logic and test against that, then create a wrapper that has the #[node_bindgen] annotation and calls the inner function. Something like this:

#[node_bindgen]
pub fn sum(first: i32, second: i32) -> i32 {
    sum_impl(first, second)
}

pub fn sum_impl(first: i32, second: i32) -> i32 {
    first + second
}

// Then unit test `sum_impl`

Let me know if that pattern works for you!

from node-bindgen.

Test failure happens because actual rust fn sum is hidden:

extern "C" fn napi_sum(
    env: node_bindgen::sys::napi_env,
    cb_info: node_bindgen::sys::napi_callback_info,
) -> node_bindgen::sys::napi_value {
   .....
    fn sum(first: i32, second: i32) -> i32 {

So one way is to move inner fn as peer:

 pub fn sum(first: i32, second: i32) -> i32 {
...
}

extern "C" fn napi_sum(
    env: node_bindgen::sys::napi_env,
    cb_info: node_bindgen::sys::napi_callback_info,
) -> node_bindgen::sys::napi_value {
   .....
   

from node-bindgen.

Seems like this is solved problem. Closing this. Feel to re-open if this doesn't the solve

from node-bindgen.

We should add this to documentation

from node-bindgen.

Hi @nicholastmosher, while your solution is simple to use when my API is minimal, I have a library exports structs and their implementations.

Using this method is practically - copy all my code just to export it.

from node-bindgen.