R: make outline and breadcrumbs work for tests and test files

[jennybc]

Our current outline doesn't know how to help with test files.

I'm seeing "No symbols found in document 'test-multi-file.R'".

[jennybc]

@juliasilge I nominate this one for inclusion in the package dev epic issue. What do you think?

[juliasilge]

Yes, makes sense @jennybc!

[juliasilge]

The outline is generated from "document symbols", which in this case come from ark. We'll need to add testthat statements as document symbols to get them to show up in the outline. From my experimenting so far, as of right now, something has to be assigned to be a document symbol that gets added to the outline, like:

## this does get added to the outline
x <- 1

## or
y = 2

## or
z <- function(i) {
    i + 1
}

## this does not get added to the outline
for (i in 1:3) {
    print(i) 
}

Alternatively, we could add an additional document symbol provider in the R extension (not ark) and write out rules for testthat document symbols in Typescript. The docs for registerDocumentSymbolProvider() say:

Multiple providers can be registered for a language. In that case providers are asked in parallel and the results are merged. A failing provider (rejected promise or exception) will not cause a failure of the whole operation.

So if for some reason it's not appropriate to add this to ark, we could do this.

[juliasilge]

I chatted with some other R folks today, and we want to focus on UI for testing in #1365 and not prioritize getting test files to show up with good content in the outline for now. We'll leave this open but I am taking it out of the R package development epic.

[jennybc]

I'm adding some recent feedback from @hadley here, because it's super related. But when someone actually works on this, it's possible these become two separate issues.

In regular R files, I can click in the breadcrumbs to see all the functions

it’d be nice if I could see all the test sections and names in a test file