cargo test always fails to run.

[HaoYang670]

Hi all,

When I run cargo test, I always get something like

error[E0433]: failed to resolve: could not find `parquet` in `io`
 --> examples/parquet_write.rs:9:9
  |
9 |     io::parquet::write::{
  |         ^^^^^^^ could not find `parquet` in `io`

Because some features are disabled.
How could I run cargo test successfully?

BTW, cargo test --features full always works well.

[jorgecarleitao]

Hey @HaoYang670 . So, the idea is: cargo test --tests covers everything that is not feature-flagged. cargo test --lib is mostly for tests covering functions that are not public (we have very few).

cargo test includes examples. Unfortunately cargo does not support declaring which feature flags each example requires, and thus we can't provide a cargo test that only tests the examples that do not depend on a feature flag.

My usual dev flow is:

If I am working on a core aspect (no feature flags), run cargo test --tests. If I am working on a specific feature, run cargo test --features ... --tests. I seldom use cargo test --features full, since the CI will handle it (and it seldom provides value - if it compiles and the tests under the feature work, very likely all is good.

Ideas on how to improve the situation are welcome, though :)

[HaoYang670]

Thank you for your reply @jorgecarleitao !
BTW, maybe we could update the development guide https://github.com/jorgecarleitao/arrow2/blob/main/DEVELOPMENT.md?plain=1#L7-L13 as:

## Testing

The simplest way to test the crate is to run 

cargo test --tests