# Testing

> How to run tests and benchmarks for geolith.

## Running Tests

Run the full test suite:

```bash
cargo test
```

Run tests with output visible (useful for debugging):

```bash
cargo test -- --nocapture
```

Run a specific test:

```bash
cargo test test_hilbert_index
```

## Test Organization

Tests are organized in two locations:

### Inline Tests

Each module contains unit tests in a `#[cfg(test)]` block:

```rust
// src/geometry/projection.rs
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_wgs84_to_mercator() {
        let (x, y) = wgs84_to_mercator(0.0, 0.0);
        assert!((x - 0.0).abs() < 1e-6);
        assert!((y - 0.0).abs() < 1e-6);
    }
}
```

Inline tests verify internal logic like coordinate projection, clipping, simplification, and tile ID computation.

### Integration Tests

The `tests/` directory contains end-to-end tests:

```
tests/
├── pipeline_test.rs      — Full pipeline with fixture data
├── parquet_reader_test.rs — GeoParquet reading and column projection
├── mvt_encoding_test.rs   — MVT protobuf output validation
└── fixtures/
    └── sample.parquet     — Small test dataset
```

Integration tests verify that the full pipeline produces valid PMTiles output from sample input.

## Running Benchmarks

Benchmarks use [Criterion.rs](https://bheisler.github.io/criterion.rs/book/) for statistically rigorous measurement:

```bash
# Run all benchmarks
cargo bench

# Run a specific benchmark group
cargo bench --bench pipeline

# Run with HTML report generation
cargo bench -- --output-format bencher
```

Benchmark results are saved to `target/criterion/` with HTML reports showing performance trends over time.

## Test Coverage

Generate a coverage report using [cargo-llvm-cov](https://github.com/taiki-e/cargo-llvm-cov):

```bash
# Install the tool
cargo install cargo-llvm-cov

# Generate HTML coverage report
cargo llvm-cov --html

# Open the report
open target/llvm-cov/html/index.html
```

## Continuous Integration

Tests run automatically on every pull request. The CI pipeline:

1. Runs `cargo fmt --check` — formatting verification
2. Runs `cargo clippy -- -D warnings` — lint checks
3. Runs `cargo test` — full test suite
4. Runs `cargo build --release` — release build verification