Support passing paths to `--watch` flag of `deno test`

[lionel-rowe]

Currently, the following works as expected:

deno run --watch=watched-file.ts other-file.ts

However, the following fails:

deno test --watch=watched-file.ts other-file.ts
# error: unexpected value 'watched-file.ts' for '--watch' found; no more were expected

It seems like there isn't currently any way to customize the files that watched with the test command. It's also somewhat unexpected that --watch wouldn't work identically between run vs test (but I guess it might need to work somewhat differently due to multiple entrypoints?)

Motivating use case: test suite includes some doc tests that run code blocks found in markdown files, so the tests should be re-run on changes to the markdown files as well as ts/js files.

[bartlomieju]

This seems very reasonable and we should support it. It should be straightforward to implement following the same pattern as for deno run so marking as good first issue.

[RyanClementsHax]

I'm considering helping out here. Is this what you mean by straightforward or is there something I'm missing.

• Argument parsing needs to be updated
• The TestFlags struct should be updated to use the same type as the RunFlags struct
• The watch_paths() function needs to be updated to handle this case since it is used in the test worker for watched runs

[bartlomieju]

@RyanClementsHax that's correct. Feel free to open a PR and ping me there if you get stuck anywhere.

[RyanClementsHax]

I haven't forgotten about this!

[RyanClementsHax]

I'm still implementing this, but I'd figure I'd ask about some friction I was seeing as it took up all my "open source time" last week to solve.

Last week, I was coming by some issues building off of main and 1.39.2. Running cargo clean && cargo build -vv failed with being unable to compile deno_runtime. It didn't give me too much error info to work off of, but are tools/techniques to pinpoint problems when building deno_runtime?

The problem seems to be solved now, but I'm just looking to see what other general things people turn to when debugging rust build problems for deno. Normally the compiler errors are helpful, but this time I didn't find them very helpful.

[ericlery]

The problem seems to be solved now, but I'm just looking to see what other general things people turn to when debugging rust build problems for deno.

I've run into some issues myself first time building Deno. In this issue, I've talk about the way I managed to build without errors, and how I got informations to debug what's happening during the build.

[RyanClementsHax]

Thanks for that. It's always nice to see how others are developing in deno

[RyanClementsHax]

Ok I have this mostly developed. I'm just not sure what to do about this line that includes the entire project directory when the --watch flag is passed.

@bartlomieju should the behavior be the following?

1. If --watch is passed, the root directory is watched as before
2. If one or more --watch=some_file.ts is passed, the root directory should not be watched, only the files explicitly mentioned, the entry point, and all files transitively or directly imported by the entry point

[RyanClementsHax]

I know you're busy. Just wanted to let you know that I'm still ready to continue work whenever you can get back to the questions above.

[muddlebee]

@lionel-rowe @bartlomieju we can close this. its working as expected

this is the correct format

deno test --watch main_test.ts 

rather than

deno test --watch=main_test.ts 

[lionel-rowe]

we can close this. its working as expected

deno test --watch main_test.ts 

@muddlebee that watches main_test.ts and any of its dependencies but it doesn't watch any other files.

Motivating use case: test suite includes some doc tests that run code blocks found in markdown files, so the tests should be re-run on changes to the markdown files as well as ts/js files.

Here's a repro
https://github.com/lionel-rowe/deno-test-watch-repro/blob/main/deno.jsonc

[muddlebee]

@lionel-rowe I tried with below test example as well.
https://github.com/denoland/deno_std/blob/main/signal/test.ts

deno test --allow-run --watch tests/util/std/signal/test.ts

[lionel-rowe]

@lionel-rowe I tried with below test example as well. https://github.com/denoland/deno_std/blob/main/signal/test.ts
deno test --allow-run --watch tests/util/std/signal/test.ts

@muddlebee This is the semantics of that command:

deno test --allow-run --watch tests/util/std/signal/test.ts
#                             ^ files to run (and watch)

The semantics I'm interested in is this:

deno test -A --watch=docs.md                       *.test.ts
#                    ^ files to watch but not run  ^ files to run (and watch)