Parquet support in Arrow requires data to test against, this data is in a git submodule. To pull down this data run the following:
git submodule update --init
The data can then be found in cpp/submodules/parquet_testing/data. Create a new environment variable called PARQUET_TEST_DATA to point to this location and then cargo test as usual.
Our CI uses rustfmt to check code formatting. Although the project is built and tested against nightly rust we use the stable version of rustfmt. So before submitting a PR be sure to run the following and check for lint issues:
cargo +stable fmt --all -- --check