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SWC Community•2y ago
Levi

How to test a visitor that uses visit_mut_script?

Let's say you have a visitor, something like this 
struct Visitor;

impl VisitMut for Visitor {
    fn visit_mut_script(&mut self, script: &mut Script) {
        // Do something with script
    }
}
struct Visitor;

impl VisitMut for Visitor {
    fn visit_mut_script(&mut self, script: &mut Script) {
        // Do something with script
    }
}
Then you create a unit test, something like 
#[test]
fn test_visitor() {
    let input = "";
    let expected = "";

    test_transform(Syntax::default(), |_| as_folder(&mut Visitor), input, expected, true);

    // Optionally do some assertions with assert, assert_eq etc on the visitor
}
#[test]
fn test_visitor() {
    let input = "";
    let expected = "";

    test_transform(Syntax::default(), |_| as_folder(&mut Visitor), input, expected, true);

    // Optionally do some assertions with assert, assert_eq etc on the visitor
}
The test function won't work because the internal code for test_transform parses the input code as a module and not a script, so visit_mut_script is never called. Is there a different function to use instead of test_transform or is there a way to make test_transform use parse_script instead of parse_module?
3 Replies
Levi
LeviOP•2y ago
So after a bit of digging it seems like visit_mut_module, visit_mut_script and visit_mut_program can be called if you use parse_program (I think?) but not parse_module which is what test_transform seems to use. Should test_transform maybe use parse_program instead? I think this should probably be the case as a test case could be either a module or a script but right now it's assuming it's always a module which I think is bad, parse_program doc states: Returns Module if it's a module and returns Script if it's not a module. so therefor test_transform should probably use parse_program correct?
kdy1
kdy1•2y ago
You are correct I guess
Levi
LeviOP•2y ago
I’ve made an issue for now, we can perhaps discuss this further and see if changing it would break anything if you are interested

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