Ashley Davis (Jun 18 2024 at 22:18): Ashley Davis (Jun 18 2024 at 22:18):I've been doing TDD of my first Roc function.
To get roc test to find my expectations I had to reference my new module from the main script.
When I added the module I got a warning (when running my tests) saying the module isn't being used.
It's not being used yet because I'm in the process of TDDing it.
How do others approach TDD in Roc? Should roc test pick up all expectations even if they are for code that isn't being used yet? Or do I just have to add every module I'm testing to the main code file and suffer the warnings while I'm TDDing?
Cheers
Ash
Luke Boswell (Jun 18 2024 at 22:20):Can you run roc test on just your new module?
Luke Boswell (Jun 18 2024 at 22:20):If it doesn't import anything then this should work ok
Ashley Davis (Jun 18 2024 at 22:21):Should something like this work:
roc test --linker legacy headings.roc
Yeah, that should work
Ashley Davis (Jun 18 2024 at 22:25):I'm getting a crash doing that:
> roc test --linker legacy headings.roc
thread 'main' panicked at crates/compiler/load_internal/src/file.rs:364:85:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Running under WSL2/Linux under Windows. It's a nightly build from a couple of days ago.
Ashley Davis (Jun 18 2024 at 22:26):Is there anyway to make roc test just pick up all tests in my project regardless of whether the code is actually used yet?
Agus Zubiaga (Jun 18 2024 at 22:27):That’s interesting. Can you open an issue for it? It might be helpful to see the output of roc check too
Ashley Davis (Jun 18 2024 at 22:28):Nothing comes up from roc check:
0 errors and 0 warnings found in 875 ms
Is that for the module or the whole app?
Brendan Hansknecht (Jun 18 2024 at 22:30):Just for reference, I have done tdd in roc before with this:
find . -name "*.roc" | entr -ccr roc test /_
Will run roc test on any roc file when it changes. That said, it won't automatically index new files. Just those that already exist.
Ashley Davis (Jun 18 2024 at 22:30):Whole app I guess.
Agus Zubiaga (Jun 18 2024 at 22:30):Try roc check {YourModule}.roc
Ashley Davis (Jun 18 2024 at 22:31):Ok wow that's a bit different.
> roc check headings.roc
An internal compiler expectation was broken.
This is definitely a compiler bug.
Please file an issue here: https://github.com/roc-lang/roc/issues/new/choose
thread 'main' panicked at crates/compiler/load_internal/src/file.rs:3556:29:
Outstanding references to the derived module
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
I've pushed the code already. I'm working on a chapter of the Roc "book of examples":
https://github.com/ashleydavis/book-of-examples/tree/main/gallery/roc
Ashley Davis (Jun 18 2024 at 22:33):In my next session I'll try an updated build and then maybe log an issue.
Pls let me know if there's any resources already out to help me understand how to TDD in Roc.
Luke Boswell (Jun 18 2024 at 22:37):List.len(headingA) looks like incorrect syntax. In roc we dont need brackets, so I think this should be if List.len headingA == List.len headingB then
Ashley Davis (Jun 18 2024 at 22:43):Oh good catch thanks.
roc check still crashes though.
Last updated: Jul 26 2025 at 12:14 UTC