swc/crates/swc_ecma_visit/tests/main.rs

use swc_common::{chain, DUMMY_SP};
use swc_ecma_ast::{Module, Program};
use swc_ecma_visit::{Visit, VisitWith};

#[test]
fn should_visit_program() {
    struct Pass1<'a>(&'a mut usize);
    struct Pass2;

    impl<'a> Visit for Pass1<'a> {
        fn visit_program(&mut self, _program: &Program) {
            *self.0 += 1;
        }
    }

    impl Visit for Pass2 {}

    let n = Program::Module(Module {
        span: DUMMY_SP,
        body: vec![],
        shebang: None,
    });

    let mut counter = 0;
    let p1 = Pass1(&mut counter);
    let p2 = Pass2;
    let mut pass = chain!(p1, p2);
    n.visit_with(&mut pass);

    assert_eq!(counter, 1);
}