cityjson-test-interop

Black-box interoperability tests for CityJSON Arrow and native CityJSON Parquet datasets.

This repository verifies that the published CityJSON Arrow/Parquet schemas are usable by independent implementations. Tests compare semantic CityJSON meaning rather than implementation-specific binary equality.

The suite intentionally lives outside cityjson-arrow and cityjson-parquet so that readers and writers can be implemented against the published specs without relying on private crate internals.

Scope

• PyArrow reads Rust-produced CityJSON Arrow streams.
• Rust reads PyArrow-produced CityJSON Arrow streams.
• PyArrow reads Rust-produced native Parquet datasets.
• Rust reads PyArrow-produced native Parquet datasets.
• DuckDB and Polars query native Parquet table files with filtering and projection.

Native Parquet tests intentionally treat nullable fixed-size CityJSON Arrow fields as Parquet lists with fixed-length semantic validation. PyArrow 23.0.1 cannot full-scan nullable FixedSizeList Parquet columns, including files it writes itself.

The existing .cityjson-parquet single-file package is not the target for DuckDB/Polars tests; that package is an Arrow IPC-backed container. Native Parquet interop uses the dataset API in cityjson-parquet.

Layout

• python/cityjson_test_interop/ contains spec-based Python artifact writers and readers.
• tests/ contains pytest scenarios.
• rust-tools/ contains a small helper binary that calls public Rust APIs only.

Requirements

• Python 3.12+
• uv
• Rust toolchain
• sibling checkouts:
  • ../cityjson-arrow
  • ../cityjson-parquet
  • ../cityjson-rs
  • ../cityjson-json

Commands

uv sync
uv run pytest

or:

just ci