wasm-bindgen/tests/all/comments.rs

use super::project;

#[test]
fn works() {
    let mut p = project();
    p.file("src/lib.rs", r#"
            #![feature(proc_macro, wasm_custom_section, wasm_import_module)]

            extern crate wasm_bindgen;

            use wasm_bindgen::prelude::*;

            #[wasm_bindgen]
            /// This comment should exist
            pub fn annotated() -> String {
                String::new()
            }

            #[wasm_bindgen]
            /// This comment should exist
            pub struct Annotated {
                /// This comment should not exist
                a: String,
                /// This comment should exist
                pub b: u32
            }

            #[wasm_bindgen]
            impl Annotated {
                #[wasm_bindgen(method)]
                /// This comment should exist
                pub fn get_a(&self) -> String {
                    self.a.clone()
                }
            }
        "#);

        let (root, target) = p.cargo_build();
        p.gen_bindings(&root, &target);
        let js = p.read_js();
        let comments = extract_doc_comments(&js);
        assert!(comments.iter().all(|c| c == "This comment should exist"));
}
/// Pull out all lines in a js string that start with
/// '* ', all other lines will either be comment start, comment
/// end or actual js lines. 
fn extract_doc_comments(js: &str) -> Vec<String> {
    js.lines().filter_map(|l| {
        let trimmed = l.trim();
        if trimmed.starts_with("* ") {
            Some(trimmed[2..].to_owned())
        } else {
            None
        }
    }).collect()
}